Minas spawns

I was on Minas yesterday with several other players.  I came in the middle and found that the Axis was spawning below gate 6 even though gates 6 and 7 were already blown.  I've never seen that particular problem before.  Simon was there and said it had happened three times in the past week.  I played the next cycle and went thru the gates quickly but had no problems.  I played another cycle more slowly and the problem did not recur.