If you really want to dive into it, you could now compare all those Revolut cards. Same card manufacturer? There’s a little text on the back. Same BIN number ranges? Same scheme, Mastercard or Visa? When were the cards issued? Does it happen again, can you replicate it?
Those are all the things that come to mind.
I don’t think it’s worth trying to figure this out in retrospect if to doesn’t happen repeatedly.