Wrong language after login

[MSoeb]

Describe the bug
After first login in an instance with German language, the first opened meeting has an English menu structure, even if the browser and the rest of the instance is in German.

I'm not sure, if it only happens after first login.

How to Reproduce
Steps to reproduce the behavior:

1. login into an instance with cleared website cache
2. open a meeting in -> wrong language.

Expected behavior
The correct language should be displayed in the meeting. In the case above it should be German.