Bull City lists it as possibly containing A/P because it's not on Capella's A/P status list yet, but I confirmed through their customer support email that it is A/P free, and Diacetyl free. Hopefully they'll update the A/P page of their site soon with the test results.
Diacetyl and acetyl in ejuice is such small amounts it's negligible. Average ejuice contains 10 parts per million. One single cig contains 6000 parts per million.
TL:DR diacetyl does not matter in ejuice
Micrograms (µg) is what needs to be compared, not PPM. The numbers you gave though are similar to what is listed for µg here though, so maybe that was just lost in translation from wherever you got your PPM numbers. It's 6000 µg per pack though, not per cig.
Those numbers aren't entirely accurate; it depends on what juice you are talking about, and how much of it you have. A lot of juices have cut out diacetyl down to really low levels, but they still have acetyl propionyl.
I had a hard time finding the acetyl propionyl levels for tobacco cigarettes. This[PDF embedded in page] is the only study with numbers that I could find, and it says 50 µg acetyl propionyl per cig, and 250 ug diacetyl per cig. It's from 1981 though, and the diacetyl numbers elsewhere have gone up from that.
Even if we assume that it's off by 100%, and the acetyl propionyl number is actually 100 µg per cig, or 2000 µg per day for a pack a day smoker, if you use one of the higher acetyl propionyl juices like this one, and compare it to a high AP juice:
You're getting 9000 µg per day if you go through a 5ml tank in one day (i go through 2-3 of those a day sometimes, so I think 5mg is a fair estimate for "average").
That's the same amount as in 90 cigarettes, or 180 if we use the original 50 µg from the study.
Also, the Diacetyl in that is low, but it's not as low as what was in that blog post earlier. It's would be 47 µg per day for a 5ml tank, not the 9 µg that they have listed (which is probably for a safer juice).
Yes, there's all sorts of other chemicals in cigarettes that are bad, plus there's the smoke itself, so they are definitely still way worse, even compared to a juice high in acetyl propionyl, but the point is that it does matter, and it is something we should be concerned about and aware of, especially if we are using high output devices and going through large volumes of juice.
A single cigalike cartridge (which contains ~1ml juice) could have 300 µg of diacetyl in it and we might say that's not that big of a deal, since it's supposed to be equivalent to like a pack of tobacco cigs, but if we take that same juice that is in the cartridge and go through 5mls of it in a day, now we're getting close to what's in a pack of cigs.
TL;DR: There's more in there than you think, and with the volume of juice that most go through in a nice tank or dripper, even a small amount can matter. We need to be aware of this.
I used Sweet butter by the gallon and just got my order of golden butter. It's the same stuff. I posted a picture to prove it was just a name change.
edit you are right, just "Butter".
Goodbye, delicious butter. Hello overwhelming vomit odor. :)
I haven't actually used Golden Butter, but I assume it uses Butyric acid.