Havoc Hammer device's lockout debuff on full charge is now also preventing Haymaker from being charged entirely. When you attempt to charge it it behaves as if you are only tapping.
Steps to repro:
Get Havoc Hammer device
Get Haymaker Rank 1/2/3
Fully charge Havoc Hammer
Attempt to charge Haymaker.
One solution is to remove the lockout entirely. Would definitely be more fun that way. But ultimately this bug was introduced during the last patch.
Edit: Nevermind, this has become a now intentional feature of the PVD. Please close this thread.