I had this same problem when gunning, in the sicilly scenario so it has been quite long term now if it is a bug.
I would think that it isn't a bug, because of this and just the way the gameplays.
Eventhough I would like to see the gunners position able to be rearmed if it is manned. I think it would much improve the point of reamring in buffs, and seeming as manned guns are going to be used much more often in the new pacth it would almost make it nessercary
Shift