Ran into a bug when playing zombies with a couple friends.

We were trying to do the origins easter egg and the game was running fine, no lag spikes, frame drops, etc. But out of the blue the game just minimized without me pressing anything to minimize it. After it minimized the games audio was still playing but I wasn't able to re-open the game.

Is this something that's preventable or is it just a bug that happens randomly?