WoT: Gun barrel Glitch

Hello Warriors,

Bangzoomkaboom emailed me the replay of his mate's Gun Barrel which very well appears to be glitched:

Have to say the lads laugh and excitement made me giggle. :)

Ive searched in the forums for other players having same issue but only could find this:

Source.

Does any of you had this glitch? If yes stand forward please.