I ordered 100ml of Boba's back in October, and I've been running out so I ordered another 100ml just last week.
I still have ~15ml of the first bottle. They are definitely different. The first bottle has a more reddish color to it, the second is more yellow. Could be time changed the first one, it is kinda old by now.
The flavor of the second is different too, markedly sweeter, tastes less like graham crackers to me. Still very good, though, and I actually welcome the change. After 5 months of vaping the same thing every single day, I get very used to the flavor and sometimes I can't even taste it at all. Having a change means that I can taste all the changes, and this is kind of fun for me.