Website error Exception: Only file CSS assets can be optimized

Running multisite on one installation. Some of the sites show this error and some don't, is there a way to clean up optimized on sites that show this error to force it to re-optimize CSS?

PHP 7.3.16
Server version: Apache/2.4.6 (CentOS)
CentOS Linux release 7.7.1908 (Core)

searched for sass, pcss, and js. found only one

/var/www/drupal$ find *library.yml | xargs grep -i js
./core/modules/media_library/config/install/views.view.media_library.yml: row_class: 'media-library-item media-library-item--table js-media-library-item js-click-to-select'

We use theme gavias_tico and there is file called gavias_tico.libraries.yml

We use the same theme for multiple website subdomains, the exception shows up on two of them but not the others. Have not tried using other theme to check.

The exception log messages show different pages url locations

Exception: Only file CSS assets can be optimized. in Drupal\Core\Asset\CssOptimizer->optimize() (line 25 of /var/www/drupal/core/lib/Drupal/Core/Asset/CssOptimizer.php).

Like this?

css:
theme:
//fonts.googleapis.com/css?family=Raleway:400,600,700,800,900: { type: external, preprocess: false }
//fonts.googleapis.com/css?family=Open+Sans:400,600,700,800: { type: external, preprocess: false }

That didn't fix it.

Before the exception, there are about 10 notices like this one:

Notice: Undefined index: type in Drupal\Core\Asset\CssOptimizer->optimize() (line 24 of /var/www/drupal/core/lib/Drupal/Core/Asset/CssOptimizer.php)
#0 /var/www/drupal/core/includes/bootstrap.inc(600): _drupal_error_handler_real(8, 'Undefined index...', '/var/www/drupal...', 24, Array)

And 2 warnings like this:

Warning: ksort() expects parameter 1 to be array, null given in Drupal\advagg_bundler\Asset\AdvaggCssCollectionGrouper->group() (line 62 of /var/www/drupal/modules/advagg/advagg_bundler/src/Asset/AdvaggCssCollectionGrouper.php)
#0 /var/www/drupal/core/includes/bootstrap.inc(600): _drupal_error_handler_real(2, 'ksort() expects...', '/var/www/drupal...', 62, Array)
#1 [internal function]: _drupal_error_handler(2, 'ksort() expects...', '/var/www/drupal...', 62, Array)

Notice: Undefined index: weight in Drupal\Core\Asset\AssetResolver::sort() (line 386 of /var/www/drupal/core/lib/Drupal/Core/Asset/AssetResolver.php)
#0 /var/www/drupal/core/includes/bootstrap.inc(600): _drupal_error_handler_real(8, 'Undefined index...', '/var/www/drupal...', 386, Array)
#1 /var/www/drupal/core/lib/Drupal/Core/Asset/AssetResolver.php(386): _drupal_error_handler(8, 'Undefined index...', '/var/www/drupal...', 386, Array)

Just to make sure, you mean to uncheck "Enable advanced aggregation"

Administration > Configuration > Development > Performance

That didn't fix it.

Just food for thought

Is there a way to clear CSS Optimizer data or all optimized data and force it to start the optimize process from the beginning?

or may be add logger line of code in the optimizer to tell us where it is coming from?

website shows

The website encountered an unexpected error. Please try again later.

To reproduce on production site,

Fill contact us form and submit or login as admin. After that the contact form and login will show "Try again ..." until drush -cr

Any ideas?

Thanks for the help,

Yes, that is started with first install of drupal 8.

Attached is enabled modules list

It is not that one, tried disabling css injector preprocessing like it says last week and that didn't fix it.

Started seeing this error after moving from D7 to D8 last year and thought it will go away once D8 gets updated with fixes.

We have one website sub-domain running on same code base and configuration, it doesn't show that error. May be something in database or some files under file system folder /files that causing it, like gz files under css/js but don't know much about how the optimizer works. All these files have recent dates though.

Disabled cron tasks and that didn't fix it.

Researched but there is not much found other than #3169757 and few other comments.

You mean to change line 25 of /var/www/drupal-8.9.11/core/lib/Drupal/Core/Asset/CssOptimizer.php

public function optimize(array $css_asset) {
if ($css_asset['type'] != 'file') {
throw new \Exception('Only file CSS assets can be optimized.');
}

to

public function optimize(array $css_asset) {
if ($css_asset['type'] != 'file') {

\Drupal::logger('module')->notice($css_asset);

throw new \Exception('Only file CSS assets can be optimized.');
}

Will that work? not sure what module, or you have better lines of code to add?

Here is the $css_asset array

Array ( [group] => 999 [browsers] => )

We disabled the CSS preprocessing for Asset Injector and it didn't fix it.

Configuration -> Development -> Asset Injector -> Css Injector and unselected Preprocess CSS

Did we miss something from #3169757 fix?

Attached is the 999 that I can find in the code base, removed the strings other than just 999.

Not sure, is that what we looking for?

./modules/asset_injector/src/Form/AssetInjectorFormBase.php: '#weight' => 999,

I searched only the *.php and *.inc files, should I search all files or that is enough?

Uninstalling the module (Asset Injector) resolved this issue.