Cursor goes right off the game..

Since the 5.14 patch my in-game cursor goes right out of the game. I usually play in a window since i have two monitors and haven't had this happen in 3 years of playing league until that patch, its continued with the latest 5.16 patch. I've mainly noticed it in arams mode. I've tried playing the game in full screen mode and the same thing happens, pans right over to my second monitor... Makes it really hard to scroll the map, have to either use the arrow keys or click on the minimap. Tried fresh install of the game. Tried fresh install of windows 7 x64 and then fresh install of the game. Also tried windows 10 pro x64 and fresh install of the game. Every other game I own (100+) works fine in a window and league used to before this patch. I refuse to have to play full screen mode and unplug my second monitor just to play league. Any other idea for a fix?