Local dimming is under energy saver I believe, and it's already off, unless expert mode is the only official way to guarantee it being off. I have under gamer mode but by switching it to laptop/notebook mode it seems to have gotten rid of the global dimming. Putting my calibration blu-ray back in to see if that did the trick.
My LG TV:
Settings > Picture
Energy Saving: Off
Picture Mode: isf Expert1
*bottom of the page* LED Local Dimming: Off