I have noticed, via the pnr.sh tool, that when I select an exit row seat it generates an SSR attached to the reservation as “$EXIT” even though it was obviously free being a PM. My assumption is that this is some sort of a flag to indicate where a passenger has paid for an exit row, should a refund ever need to be processed, or to otherwise prove they were entitled to that seat. I have seen that SSR remain attached to the PNR even if the seat is changed.

My guess is that because that SSR stayed attached, it conflicted with the “PETC” SSR that became attached once you added the pet and kept causing system confusion. So basically an IT glitch.

As someone who travels with a pet once a year, this is certainly a good datapoint to have!