The juice is said to be made in the US sent to the shop. It is made just for that shop and has the shop logo on it. I was told it shouldn't need steeping but I have had it for close to two months by now and I try it every so often but it just gets worse.
Let it sit for a day or two with the caps off. After that, put the caps back on and every day give it a good shake for at least a week. I also found that some flavor types require more steeping and shaking then say a tobacco flavor. Any lemonaide flavor seems to need at least one month to steep before it mellows out.
I also rarely buy shop juice anymore, just because of the problem you described. I taste them at the shop and when I get them home they don't taste the same. If they rebrand their juices and won't tell me who the supplier is, I tend to shy away, only because we know some shops it's about profit margins and I want to make sure I know it's safe to vape.
Another thing to think about is... do you have a burnt coil? What kind of tank are you using? What mod are you using? And do you know the % of PG in the liquid?