I’ve not heard that one before, and I’m struggling to work out how it might happen. My best guess is that there was a date mismatch on the bus and it didn’t recognise the travelcard.
I don’t think this will automatically get picked up, so I’d advise calling the helpline. I’d be interested to hear their thoughts on how it might have happened. Also, unless you’re happy to have £1.50 tied up on the card you can ask for the refund to be sent to your bank. It depends whether you regularly use PAYG for out of zone journeys or not.