Group role name is untranslatable, "group_type" parameter is missing from the route

i have the same issue. I tried to investigate...
the route "entity.group_role.config_translation_overview" is generated from the module "config_translation" in core.
After looking at the generated route, it was looking fine with the parameter "@group_type" inside the route path.
so i still don't yet understand the underlying problem with this route and the missing parameter error.

Getting similar error when i try to delete a node created through Group module:

Symfony\Component\Routing\Exception\MissingMandatoryParametersException: Some mandatory parameters are missing ("plugin_id") to generate a URL for route "entity.group_content.add_form". in Drupal\Core\Routing\UrlGenerator->doGenerate() (line 180 of /var/www/public/drupal8.x/core/lib/Drupal/Core/Routing/UrlGenerator.php).

Referrer: http://{{base_path}}/group/1/content/6/delete?destination=/group/1/nodes

@micheljp, Check http://www.drupal.org/i/2908830

@jochemvn thanks so much for the info. Did this patch get applied to 8.x-1.0-rc1?

no, you have to apply it yourself, or use the dev version (would never recommend that btw)

Seems like a duplicate of #2908830: Crash when clicking "delete" any group content, please re-open if the problem persists with the latest dev.

This is still an issue for me in the latest dev.

Attached patch fixed it (no tests sorry). - It overrides the Drupal\config_translation\ConfigEntitityMapper class for GroupRole entities. The idea comes from how NodeType works and the way it also overrides the ConfigEntityMapper (see https://api.drupal.org/api/drupal/core%21modules%21node%21node.module/fu...).

There is another issue available (with a similar patch) at #3014651: Can't translate group roles. I'll close this issue as a duplicate, so we can focus our efforts in the related issue.