I've had that happen more than once. I really liked a juice that was made fresh. Right out of the mailbox it was good. I filled a couple carto's and was a happy camper. When the carto's ran out of juice, I refilled them. I took a hit and had to check the bottle to be sure it was the same. It had totally changed into a flavor that I really couldn't vape. I don't want to say which supplier I got it from because they do sell quality juice. It's just that I didn't like what the juice had become after some steep time. I had this happen to another juice as well, but it was a marginal flavor to start with. It just turned unvapable. IMO.
I use only carto's at this time. When I used atty's and carts, I had several occasions that the flavor turned bad because of the atty's. After changing the atty or cleaning the same one I used, the juice that I thought had turned bad began to shine again
I try to keep my hardware simple these days. I use Carto's and a Tornado/ Ego. I stopped with HV and LR atty's, dripping. The less gear in the mix seems to have less hassles and makes vaping to me more enjoyable. I got so ...... one time, I threw a good set of hardware off my boat when I was fishing. Ya think I need anger managment class? I just got fed up with getting burnt taste and juice leaking all over. Leaking, burning taste, still happens now and then, but nothing like I was getting. The Ego extra large carto's seem to help with those issues.
Dave