Bug/Issue Updated event seen ID list?

(1.5 spoilers )

Hello, on one of my main farms Leo decided to randomly move back to the island after he already got his new treehouse next to Linus' tent? I'm not exactly sure how to fix this but I thought maybe if I delete the event seen id for his 6 heart event and re-trigger it he would move back to the mainland. Issue is I can't figure out which id belongs to him and I'd really rather not try every single id. Is there a list or does someone have a better solution?