Iron cub not shooting

Just came back since last Nov and been trying out Iron cub. I notice iron cub is very responsive for about half a min or so then it becomes idle and not shooting at all. Is it because its fuel has run out? The yellow bar in the middle bottom is still plenty but iron cub just doesn’t shoot. It usually takes another 20-30 sec before it starts shooting again. I thought it was some known bug but I did some googling and couldn’t find any relevant info. I know certain weapons like explosive minigun has cooldown but I’m experiencing this issue for all weapon types.

When this happens, try switching to iron bear, summon/eject and switch back.