I was just playing the sc campaign and was in the 9th zerg level, Invasion of Aiur in cartoon mode when I encountered this bug:
I had just wiped all the toss bases and sent in my drone to retrieve the crystal. I did not have any defending to do for the 10 minutes so I just piled my guys around center and started a hatchery on the other side of the crystal. after the 10 minutes elapsed I had a notification warning me there was no room for the crystal to spawn.
Now I cannot complete the level without doing it all over and frankly that took so much time and effort ill sooner just uninstall this glitchy misadventure into nostalgia.