I have been trying to find an active or semi recent thread on this issue. I have two challenges that are negative 1 billion or so. Heal Plz and Set the World On Fire. Is there a fix for this or am I just out of luck? This is the last one I need to platinum.
Randomly they will reset and trigger the glitch again.
The easiest workaround to this really is on a new character and get the trophy BEFORE you reach UVHM. Mostly it’s the slag-licked challenge that glitches, and since you don’t need slag until UVHM, it’s better to get it done in NVHM or TVHM as a result. Also your damage output is much lower on these playthroughs so you aren’t likely to hit the numbers you’d need even if you did use slag.
I had the very same problem a short time ago and doing it in TVHM to make sure helped out. You can drop to NVHM to make the annoying ones easier, such as Open Wide.