Game randomly closing, and items being used on accident

Playing league like usual and it suddenly closes out. The other screen where you select your champion is still there though and it just has the rejoin button which works fine. Heard it happens to someone else in my team in one of my games, what gives? Over the last two days it has happened to me 3x, and it happens on other days also.

I accidentally have my items used when moving them around in my inventory. I very specifically made sure to hold down my mouse click while moving them and they still go off like 80% of the time. Are there any options to prevent activating inventory items via the mouse? or just fix this issue.