Language selection not stable in Agent Interface

Hello,

I noticed a strange behavior of the selected language in my Agent Interface:

1. I go the my Agent Interface (and therefore the Topic Review opens, in French my default language)
2. I switch to English
3. I go to Statistics > Overview
4. and the language is back to French?
   => Strange.
5. I switch again English
6. then the central area of the Overview (with counters and curves) never reappears again.
   => Even more strange.

Is there something wrong with the language selection?

Best regards.