Had a similar problem, turned out to be the iCUE software for my Corsair mouse. I replaced the CUESDK DLL in C:\Program Files (x86)\Neverwinter_en\Neverwinter\Live\x64 with a far newer one I downloaded from from the SDK website at https://github.com/CorsairOfficial/cue-sdk/releases
Tried a few dungeons, Tuern was fine, nDemo was a disaster, we got absolutely murdered. RLQ was no real problem. Haven't tried any of the high end stuff yet, still getting a feel for how the new stuff works, today will be looking at L80 gear and stats seeing as I hit 80 last night
My OP is rocking her way through Undermountain, levelled to 80 with no problems using my L70 gear. Have I had to adjust a bit ? Yes Do I still have a playable OP ? Yes Can I tank in dungeons ? Um, nope, the maxim in red is dead applies to OP now as well, learn to move.