Symfony version(s) affected: 4.4.5

Description
After updating symfony/dependency-injection from 4.4.4 to 4.4.5 my one form extension is not autoconfigured (tagged) by Symfony framework. If I remove manual configuration of another form extension from services.yaml, the first one is properly autoconfigured (tagged).

How to reproduce

1. Clone my project: https://github.com/TomaszGasior/RadioLista-v3. Chechout 44f1ef41f1dd115f3405730bc8eaee512d10d325 commit where all dependencies except symfony/dependency-injection are up to date at the moment where I write this text.
2. bin/phpunit -> tests should pass
3. Update symfony/dependency-injection to 4.4.5.
4. bin/phpunit -> Tests related to adding, removing and editing radio stations should fail. Twig templates of these pages rely on variable from RadioStationEditExtension form extension which is not autoconfigured.
5. Remove manual configuration of App\Form\Extension\ValidationFlashErrorExtension from services.yaml. (My app contains two form extensions. ValidationFlashErrorExtension needs to be set up manually to get special priority.)
6. bin/phpunit -> tests should pass