Probably just an unfinished event/progress point. I ran into this same problem in the same place.
Viewing post in The Kindhearted Hero Harold Dies! jam comments
I've seen the game played further; you just have to continue navigating as an invisible player. I remember there's an ending, but not sure if I want to continue the game navigating like this... there's kind of quite a lot to walk around on for the rest of the game, and all in this invisible player state. (T_T)
EDIT: OK, never mind. I decided to give it a try, and just completed the game. Here are the details of what to expect: https://itch.io/post/7593504