Found 2 broken (as in glitchy not overpowered) power up combinations
Spin Shot+Echo=Crazy bullets going through walls and getting stuck in walls. I saw this with heat seeking+wall bounce as well so it might be wall bounce in general but it was much more noticeable with spin shot.
SharpShooter+Turret= Turret being tossed across room into wall continually over and over (salty about this one because it has a whole story).
I'll probably find more with my great combination of greed for loot and terrible luck.