Sorry if this has already been reported; I just started playing again for the first time in years, but didn't see any reports about this in this forum.

The bug: the 5* weapon gran faust can be brought into PvP games where the highest level gear is meant to be capped at 3*, and even 1* matches.

How to fix it: a developer will need to restrict this 5* weapon to T3 PvP, the same as all other 5* weapons.

Edit: Looks like this applies to all 2, 3, 4 and 5* gear being glitched into T2 and even T1 PvP.