Here's the reprod method:
Use Infernus's 2nd Ability;
Get Interrupted by something during the first frames of channeling.
Infernus gets locked in his 2nd ability state, being unable to dash (although double jumps and air-dashes are doable) and crouch (camera gets lower, hitbox stays the same). It's still possible to use weapon and abilities in this state, and re-using the 2nd ability fixes the bugged state.
Use Infernus's 2nd Ability;
Get Interrupted by something during the first frames of channeling.
Infernus gets locked in his 2nd ability state, being unable to dash (although double jumps and air-dashes are doable) and crouch (camera gets lower, hitbox stays the same). It's still possible to use weapon and abilities in this state, and re-using the 2nd ability fixes the bugged state.