I seem to be constantly changing and adding to my flavor collection so I have only purchased 2 4oz. bottles (and neither was Capella's). I had no issues with either one.
But, while I was reading your's, and the other's posts, I did have some
possible causes come to mind. I could also be
completely off the mark so feel free to cry "Baloney!" or simply ignore me.
My thoughts in no particular order:
1. As previously mentioned: settling or separation. I have no idea about Capella flavors, but I know TFA at least cautions that certain flavors can separate or have particulates form in a few flavors. They note that this can be reversed by shaking and/or
gentle warming (with shaking) to re-blend the concentrate.
2. Hand in had with #1: temperature exposure. From making a couple of my own concentrates from crystals (menthol, EM), I have learned that any given carrier (PG, VG, PGA, water) has a saturation point, where it will no longer dissolve and keep in solution, a particular ingredient, and it is different for each. Heat will accelerate this and temporarily increase this level of saturation (super saturating the carrier). But, once it returns to room temp, the excess concentrate falls back out of solution. So, I would think, the opposite would hold true too.
If your most recent purchase was exposed to any of the cold weather we have had this winter (e.g. while in transit) it is possible that it caused something to drop out of solution. Perhaps a very gentle warming (maybe 85-90F) followed by a vigorous shaking
might(?) help.
3. Age? You mentioned that Capella was able to tell you you could expect a year's shelf life on your 4oz. Do you still have your 13mL bottle? Perhaps they could tell you how much of an age difference there is/isn't.
My thinking here is if there is a considerable difference; maybe maturity (like a wine aging well), or staleness (flavor fade) could be an influence.
If you feel, or Capella gave you the impression, this 4oz. bottle is on the young side, you might park it away for a few months and then revisit.
4. Did you buy both from the same vendor (ecigexpress)? How long it was sitting in the warehouse (age), warehouse conditions (temp, light exposure),
might have some influence.
5. Did you ask, or did Capella mention, if BBJ is one of their flavors that is/has undergone reformulation? I think they have a list somewhere on the company website of flavors that they are reformulating. Could this be one of them and you liked the old formulation but don't care for the new?
6. Just plain old bad luck: I imagine Capella does what it can to maintain consistency. But, I would guess, they are not immune to one slipping by. perhaps it was the very first bottle poured off of a master batch and had not been fully blended, or it was the last bottle out and the master batch experienced a bit of separation.
7. Your own palate has changed: have you noticed any other identifiable changes in flavors you once liked/hated and now hate/like? I don't know how long it has been since you last had BBJ. If it was recent you can probably toss this idea right out the window.
I am sorry you have had such a disappointing experience. I am a little surprised neither ecigexpress nor Capella offered to replace it. That does not sound like very good customer service.
I also wouldn't throw in the towel on this particular flavor yet either. If this specific bottle is not salvageable; I would try ordering one more time from a different vendor and see if it is any better.
I hope you can find a happy resolution. Best wishes!