This is what it looks like after a day of steeping... i use a milk frother to mix my juice... could that have anything to do with there still being bubbles a day later???
From the picture I can't tell if they're bubbles, but I can tell you that FA Mellow Sunset leaves some residue that looks like bubbles at the top of the juice and it disappears when you shake it
Some people have commented that the frothers do too good of a job and may cause too much air/air bubbles. Now I don't know how much truth there is to that since I've never used one, but it seems a little bit like overkill to me to use one. Shake shake shake shake shake seems to work just fine. I'd give it a try and see if maybe you overmixed(?) it if that's possible.
I usually heat up a mix under hot tap water until it becomes viscous, give it a good shake, let it sit for a few days and it turns out pretty good. The milk frother I could see my clumsy self having e-juice on the walls in a heart beat!