In my example quoted above, the restaurant is on Toast and is on Resy but still did not trigger the credit, apparently because the Toast transaction is associated with a different location than is on Resy. Even though there was no indication of this to me at purchase time - I specifically purchased through the Toast page for the location that is on Resy. The same link that would have allowed me to order takeout from that location. I do think that probably 99% of the time it will work and I found a weird situation, but it's not guaranteed.