Only one front page for sites working

Sorry, but I can't get this to break anywhere but on pantheon test and live environments which leads me to the conclusion that it has something to do with their handling of caching. For a bit more background both of my front pages are basic pages with the source set, so they'll forward if pulled up on the wrong domain. Digging into the new "/domain/domain_source/src/HttpKernel/DomainSourceRouteProvider.php" I notice that the 'cid' does not distinguish between domains, which leads to the exact same cache ID for both of my sites on the front page:
route:[language]=en:[query_parameters]=:/

I went ahead and added the domain to the cache ID and tested my issue and everything appears to be working correctly for me. There may be a better way to go about this, but I think it at least helps pinpoint where I'm having an issue. See my attached patch.

Thanks for the quick response @mably!

That's interesting. I'm using the domain_config module and setting this through Basic Site Settings:

My 2 domains are as follow with my included patch:
route:[language]=en:[query_parameters]=:/:[domain]=oit.ddev.site
and
route:[language]=en:[query_parameters]=:/:[domain]=data.ddev.site

The domain modules I currently have enabled are:

• domain
• domain_access
• domain_alias
• domain_config
• domain_config_ui
• domain_source
• domain_theme_switch

I think domain_theme_switch is the only one that's not included in the core domain module. I hope that's helpful.

Here's a dump of the $cached_value for each domain, let me know if I'm misunderstanding what you need.

data site:

Array
(
    [path] => /node/31531
    [query] => Array
        (
        )

    [routes] => Symfony\Component\Routing\RouteCollection Object
        (
            [routes:Symfony\Component\Routing\RouteCollection:private] => Array
                (
                    [entity.node.canonical] => Symfony\Component\Routing\Route Object
                        (
                            [path:Symfony\Component\Routing\Route:private] => /node/{node}
                            [host:Symfony\Component\Routing\Route:private] => 
                            [schemes:Symfony\Component\Routing\Route:private] => Array
                                (
                                )

                            [methods:Symfony\Component\Routing\Route:private] => Array
                                (
                                    [0] => GET
                                    [1] => POST
                                )

                            [defaults:Symfony\Component\Routing\Route:private] => Array
                                (
                                    [_controller] => \Drupal\node\Controller\NodeViewController::view
                                    [_title_callback] => \Drupal\node\Controller\NodeViewController::title
                                )

                            [requirements:Symfony\Component\Routing\Route:private] => Array
                                (
                                    [node] => \d+
                                    [_entity_access] => node.view
                                )

                            [options:Symfony\Component\Routing\Route:private] => Array
                                (
                                    [compiler_class] => Drupal\Core\Routing\RouteCompiler
                                    [parameters] => Array
                                        (
                                            [node] => Array
                                                (
                                                    [type] => entity:node
                                                    [converter] => paramconverter.entity
                                                )

                                        )

                                    [_access_checks] => Array
                                        (
                                            [0] => access_check.entity
                                            [1] => access_check.domain
                                        )

                                    [utf8] => 1
                                )

                            [condition:Symfony\Component\Routing\Route:private] => 
                            [compiled:Symfony\Component\Routing\Route:private] => Drupal\Core\Routing\CompiledRoute Object
                                (
                                    [variables:Symfony\Component\Routing\CompiledRoute:private] => Array
                                        (
                                            [0] => node
                                        )

                                    [tokens:Symfony\Component\Routing\CompiledRoute:private] => Array
                                        (
                                            [0] => Array
                                                (
                                                    [0] => variable
                                                    [1] => /
                                                    [2] => \d+
                                                    [3] => node
                                                    [4] => 1
                                                )

                                            [1] => Array
                                                (
                                                    [0] => text
                                                    [1] => /node
                                                )

                                        )

                                    [staticPrefix:Symfony\Component\Routing\CompiledRoute:private] => 
                                    [regex:Symfony\Component\Routing\CompiledRoute:private] => {^/node/(?P<node>\d+)$}sDu
                                    [pathVariables:Symfony\Component\Routing\CompiledRoute:private] => Array
                                        (
                                            [0] => node
                                        )

                                    [hostVariables:Symfony\Component\Routing\CompiledRoute:private] => Array
                                        (
                                        )

                                    [hostRegex:Symfony\Component\Routing\CompiledRoute:private] => 
                                    [hostTokens:Symfony\Component\Routing\CompiledRoute:private] => Array
                                        (
                                        )

                                    [fit:protected] => 2
                                    [patternOutline:protected] => /node/%
                                    [numParts:protected] => 2
                                )

                        )

                )

            [aliases:Symfony\Component\Routing\RouteCollection:private] => Array
                (
                )

            [resources:Symfony\Component\Routing\RouteCollection:private] => Array
                (
                )

            [priorities:Symfony\Component\Routing\RouteCollection:private] => Array
                (
                )

        )

)

OIT site:

Array
(
    [path] => /node/32161
    [query] => Array
        (
        )

    [routes] => Symfony\Component\Routing\RouteCollection Object
        (
            [routes:Symfony\Component\Routing\RouteCollection:private] => Array
                (
                    [entity.node.canonical] => Symfony\Component\Routing\Route Object
                        (
                            [path:Symfony\Component\Routing\Route:private] => /node/{node}
                            [host:Symfony\Component\Routing\Route:private] => 
                            [schemes:Symfony\Component\Routing\Route:private] => Array
                                (
                                )

                            [methods:Symfony\Component\Routing\Route:private] => Array
                                (
                                    [0] => GET
                                    [1] => POST
                                )

                            [defaults:Symfony\Component\Routing\Route:private] => Array
                                (
                                    [_controller] => \Drupal\node\Controller\NodeViewController::view
                                    [_title_callback] => \Drupal\node\Controller\NodeViewController::title
                                )

                            [requirements:Symfony\Component\Routing\Route:private] => Array
                                (
                                    [node] => \d+
                                    [_entity_access] => node.view
                                )

                            [options:Symfony\Component\Routing\Route:private] => Array
                                (
                                    [compiler_class] => Drupal\Core\Routing\RouteCompiler
                                    [parameters] => Array
                                        (
                                            [node] => Array
                                                (
                                                    [type] => entity:node
                                                    [converter] => paramconverter.entity
                                                )

                                        )

                                    [_access_checks] => Array
                                        (
                                            [0] => access_check.entity
                                            [1] => access_check.domain
                                        )

                                    [utf8] => 1
                                )

                            [condition:Symfony\Component\Routing\Route:private] => 
                            [compiled:Symfony\Component\Routing\Route:private] => Drupal\Core\Routing\CompiledRoute Object
                                (
                                    [variables:Symfony\Component\Routing\CompiledRoute:private] => Array
                                        (
                                            [0] => node
                                        )

                                    [tokens:Symfony\Component\Routing\CompiledRoute:private] => Array
                                        (
                                            [0] => Array
                                                (
                                                    [0] => variable
                                                    [1] => /
                                                    [2] => \d+
                                                    [3] => node
                                                    [4] => 1
                                                )

                                            [1] => Array
                                                (
                                                    [0] => text
                                                    [1] => /node
                                                )

                                        )

                                    [staticPrefix:Symfony\Component\Routing\CompiledRoute:private] => 
                                    [regex:Symfony\Component\Routing\CompiledRoute:private] => {^/node/(?P<node>\d+)$}sDu
                                    [pathVariables:Symfony\Component\Routing\CompiledRoute:private] => Array
                                        (
                                            [0] => node
                                        )

                                    [hostVariables:Symfony\Component\Routing\CompiledRoute:private] => Array
                                        (
                                        )

                                    [hostRegex:Symfony\Component\Routing\CompiledRoute:private] => 
                                    [hostTokens:Symfony\Component\Routing\CompiledRoute:private] => Array
                                        (
                                        )

                                    [fit:protected] => 2
                                    [patternOutline:protected] => /node/%
                                    [numParts:protected] => 2
                                )

                        )

                )

            [aliases:Symfony\Component\Routing\RouteCollection:private] => Array
                (
                )

            [resources:Symfony\Component\Routing\RouteCollection:private] => Array
                (
                )

            [priorities:Symfony\Component\Routing\RouteCollection:private] => Array
                (
                )

        )

)

I took a patch of your changes and everything worked as expected on our test environment. Thanks so much for looking into this so quickly, I'll deploy the patched version of the module tomorrow to our live site.

@mably, I just deployed to our live site and everything appears to be working as expected. This fixed it for me. Thanks again for the help.