I posted this over on Bogleheads as well, but thought it could help someone here as well if it hasn’t been discussed.
I thought this might shed some light on the UA TravelBank issue.
If you choose the option to load YOUR OWN TravelBank, it will code correctly and you will get your credit. If you choose the option to load SOMEONE ELSE'S TravelBank (gift), it will code differently and you will not get your credit. Unless you get a sympathetic rep willing to manually apply it.. but you are risking exposing this for everyone else.
I have tested this a few times, and it has been consistent for me on my BoA PRE card.
FWIW, this also seems to be the case for the Amex incidental credits as well.