Could be primer taste from the new atomisers. Try dripping two drops directly onto the atomiser, let it soak in for a few seconds, then plug the cart back in and
vape away. It should clear up in a while.
Another possibility is that the carts ran dry at the same time the primer finally went away and now you're getting the taste of hot cart filler. It would be a bit of a coincidence, but those happen all the time
Either way, you want to make sure that the cart filler is moist and that the atomiser wick (the wire mesh bit) is in contact with it. Some people like to pull the cart filler up a little and make a little well in the centre to maximise the surface contact and thus the vapour production.
A final thought is that you're holding the switch closed for too long and overheating everything, perhaps because the atomisers aren't yet broken in and producing the full amount of vapour. You want to be pressing the switch for no longer than about 5 seconds at a go, and letting things cool down in between drags. The atomiser will start producing more vapour as it breaks in, so try and be patient in the meantime and not strain the poor thing
