The off thing is, you mentioned in the OP that it has a freshly created wallet with zero balance.
While in BlueWallet, if its data (not cache) is totally cleared, it should start without any wallet at all.
Just a blank wallet card with "Add a wallet" prompt.
Or do you mean you created that wallet after the wipe?
No, I didn’t create any wallet.. All I found was a new wallet all of a sudden.
Weird, definitely not the default fresh BlueWallet behavior.
At least you can rule out the probability of the app's data being wiped in this case since it shouldn't have a wallet in that case.
BTW, your first test's result is promising.
I've also tested it and BlueWallet only kept the wallet storage instance that was active when I disabled wallet encryption.
The rest are gone.
So can be this case:
That zero balance wallet must be one of your decoy wallet and while it's open, you've disabled 'wallet encryption' deleting the rest of your plausible deniability encrypted storage(
s).
And it looks like it's intended since one of the authors mentioned in this issue that it'll actually do that:
github.com/BlueWallet/BlueWallet/issues/1039#issuecomment-626800193