I don't know how It happen but sometimes you can cloak on red color (moment cloaking) and when you'll be fully invisible It's return to Blue (blue side). Here is example of something similiar http://uppix.net/a/d/b/095d6f34c0217701 ... f83821.png (big picture)
But It can happen also on Crossfire. Like I said... I saw someone cloaking on red , and later It was on blue (since I was in blue team)