I inadvertently noticed this bug today, and was able to reproduce it.
If the information on Wowhead.com is correct, Alchemists get seven charges per day of the Transmute: Awakened Air recipe. I had made a few today, and then joined a PVP Brawl (Packed House). When I got out, and went back to make the remainder of my charges, I noticed the count had reset from whatever it was (3 or 4) back to 7. I did a couple of more transmutes, queued up for another PVP Brawl, and when I exited the charge count was back to 7 again.
I noticed the same issue, pretty sure this is not intended, but the most frustrating part is that you can be sure when the “normal reset” will come, since it reset every 20 minutes.
I’m trying to be fair about this, not exploiting it, but knowing when to use your transmute without the exploit and use your normal CD, is pretty much impossible (when it literally write “1/10 available” without any timer, and when 15 minutes after you have “10/10 available” how can you know that the CD is not recharging ever 2 minutes ? … you can’t)
Just realized/noticed this today and was able to reproduce it. It seems like the reset happens the moment you enter a battleground or pvp instance.