Yes, banks do screw up transactions at times. I always have my phone with me, but I keep the volume down. The bank sends an alert at the time of a charge, but I don't hear it and only learn about it hours after transaction.
Thus far, I have managed to salvage all those purchases after-the-fact. The bank is making sure my card hasn't been stolen. BUT I am not always being challenged by the bank when I make a purchase and find some of them are typical for me, rather than something they should find suspicious.
Ah, well.