Going into Fullscreen/alt-tabbing in/out of Fullscreen isn't working.

So I just tried to play a match since the new update, and I encountered this bug where I alt-tabbed out of the match loading screen to look at something else for a second on one of my internet tabs, and when I tried to alt-tab back in the screen would go black and then kick me back to my desktop/internet page instead.

Tried disconnecting and reconnecting but that did not fix the issue.