Picking up a flag in a game of CtF seems to cause a random object to disappear. In the most recent occurrence the words "Picked up Wall" appeared over my capturing Lizardman's head. In the attached screenshot you can see a wall has disappeared, without being destroyed. Although I don't have any more support to give right now, this isn't the first time Capture the Flag has behaved... oddly.
Ha ha ha, wow! Okay. Putting it on the "to-fix" list. :D