I just got this bug too. I can walk to other towns near Branch and leave to get the world back to Merged world but since Branch is on the island now, I cannot go and get airship back T_T
Grateful for you validating what myself and others are seeing.
Hoping that the "check for Coral" that AFCToriel mentioned will be put in place on the next update. This game is so good, and I can't wait to be able to start playing it again!
