Not sure if this is the right thread for this, but:

tl;dr transactions approved, then declined, then approved again?!

I recently paid for 3 bus trips in Scotland by tapping my phone (Google Pay) to pay with my CSR. In all 3 cases the driver asked where I was going, keyed in some stuff, then I tapped, got the checkmark on my phone, and it appeared approved on their terminal.

1. Islay, £2.20 single trip, no receipt
2. Islay, £6.10 round trip, receipt/return ticket was printed out
3. Glasgow airport express, £10.50, receipt/ticket was printed out

What's interesting is that for rides 1 and 3, some time after payment (maybe 5-15 minutes) I got a push notification on my phone that the transaction had been declined. Then even later after that (like 4-5 hours later) I got another push notification that the transaction was approved. I guess all's well that ends well, but

Also of note, I have 10+ other contactless transactions on this same trip that have all gone through normally, all interleaved with these bus rides, so Chase obviously considers me to be legitimately traveling in Scotland. Unless their algorithm thinks transit-related expenses are at greater risk of being fraudulent or something...

Or maybe the common element is the card processor/backend used by the bus operators. In the case of all 3 bus rides the payment terminal on board the bus looked like this: