[Q] Knock On not working after T Mobile OTA

I have been a lurker around here for some time, but never posted. So Howdy!

I am having some troubles with my LG G2. I have loved the phone so far, and has custom TWRP recovery and rooted. Other than that the device was stock with some very minor mods (xPosed framework, etc..

I stupidly forgot that I had TWRP installed, and I chose to take the recent T Mobile OTA. The phone wouldnt boot past recovery despite a factory data reset. I flashed the stock rom (tried both D80110C and D80110G) to no avail. factory data reset again, re root, installed TWRP again, cleared cache and dalvik, and everything was fine EXCEPT the knock on feature doesnt work. Knock on works just fine, but I cannot knock to wake the device. The power button wakes the device just fine.

Anyone have any thoughts?

Also,

I was considering flashing a rom, like Gummy rom. I don't really have any hypothesis behind this, as I have already flashed the stock rom kdz twice now.