[BUG] Double XP glitch

Question

If the app language differs from the website language (Russian and English respectively in my case), after a topic is completed on the site - it stays unmarked in the app - thus allowing to re-complete it and earn XP again for its 2nd completion.
This doesn't work vice versa, neither if languages are the same.
Seems like a glitch.

Answer 1

Interesting!

Answer 2

Really, very interesting!