This just happened to me.

On level 7 with 4 stars.
Win a PvP (on a win streak)
Got to level 6 with 2 stars (as it should be)

Win next PvP
It shows me at level 7 with zero stars and gives me 2 stars for the consecutive win = level 7 with 2 stars (instead of level 6 with 4 stars)

Win next PvP
Again it shows me at level 7 and gives me 1 star ignoring the consecutive win = level 7 with 1 star (instead of level 5 with 2 stars).

This keeps on happening to me.
It took me ages to get away from level 14 despite always winning.
Not amusing.

The new bunker event has been running for two weeks now and the very obvious bugs that affect gameplay haven't been fixed.
Sad.