BlackJack.fun's team should reply transparently and comprehensively about the bugs (if they are really bugs) mentioned above.
Such a young site should be managed well in the communicational approach to community, no matter what kind of issues are.
I do not think that it is a bug because I am sure it just because of the code as well, they should add something like if J, Q and K hit Ace then it should be automatically win. I am sure their code is read Ace is 1 or 11, so it does not really big deal anyway to have something like this. You can stand and get exactly the payout but they need to change their code as well so people do not missclicked this to add some cards again