Your hunch is correct, it has to do with Band of Misfits being "that card" until it leaves play. Note that Donald has not always ruled the interaction this way. Originally it was always the first card you chose, and you can hold me partially responsible for arguing that's not how it should be (i might not have been the only one though, i just don't remember others saying it). BoM is a card with a lot of possible readings - this one is less intuitive (which is probably why Donald didn't want it originally), but it is a tad more inherently consistent. I play Band of Misfits, no wait, i play Feast, i play it again, let's see what it is, aha, it's Band of Misfits. It's certainly not the prettiest edge case.