Acer XB270HU ULMB Issue with my screen, or drivers maybe? Baffled

Question

Greetings!  I bought this XB270HU earlier this month and I absolutely love it.  It seems like G-Sync works like a charm, and that 144Hz refresh rate is wonderful.  There's some slight bleed in the upper left that can be seen with black bars around some videos, but never in the videos themselves.  Considering that is the only way it can be spotted, I figured I finally found a GREAT monitor.  My old one was a Dell S2440L that had outstanding contrast and zero bleed, but had massive overdrive issues.   While everything is going great, I chose to use ULMB sparingly since it bothered my eyes the very first time I tried it out, though the visibly dimmer screen didn't bother me.  For the record, this monitor is one that supports ULMB at 120Hz and if you try to enable it at 144Hz, the monitor will flash a message up saying it can only be used at 85 100 and 120 Hz.  So, it *does* work at 120Hz.  I am sure I may have used nvidia's GeForce Experience to update the graphics drivers at least twice out of habit, and Windows Update installed an XB270HU driver as well.  I recently went to turn ULMB on at 120Hz to use it with a movie, and was shocked to see that the screen got *brighter* instead of dimming.  I chose 85 and 100 Hz to see, and it brightened as well, to the same settings.  I don't really understand at all what happened, but it feels as if its not even using ULMB.  Since it was clearly working and suddenly is not, is this a driver issue from an update, or did something go haywire inside the monitor?  I never tinkered with anything other than the brightness levels.  I have the 144Hz Gsync mode at 50% Brightness instead of the 36% that i had it on before and when I turn ULMB on at 30% brightness, it looks much brighter than it does now.  I find this incredibly strange and was hoping someone could shed some light on this, or help me fix it.   Some Specs:Windows 8.1 64bit (updating to 10 soon)Intel Core i7-3770K @ 4.4GhzASUS Maximus V Formula BIOS 190316GB (8GBx2) DDR3-2133 G.Skill RipJaws X series memoryeVGA GeForce GTX 980 Ti SC+ ACX 2.0 Using the DisplayPort cable that came with the monitor still.

Answer 1

acheron,
Could you please PM (private message) me the following information, I believe that we can update the firmware and fix that dimming/brightness issue.
Serial number:
Contact name:
Contact number:
Email address:
Shipping address:
Purchase date:
Resolution attempting to use:
Max resolution monitor will work at 144 Hz without issues:
Video card(s) is use:
Video connection(s):
Symptoms: