Double execution of finishers when using Typo3 Forms inside of container #504

The following picture shows a translation that is in Connected Mode. The same structure is used in both languages. To the 1-Column Group was placed the Form Element. For these elements the translation was created.

With this solution, if I fill out the form and submit it, all Form Finishers are executed twice.
Example: I receive the email twice.

When I turn off the 1-Column Group in the German translation, then the finishers are executed only once.

Can you confirm that this is some kind of bug in b13/container ?

Best regards,
Miki