Hi! Thanks for your kind words - and for reporting this bug.
Although I have heard of it a few times before I could never figure out why it appears, and why I didn't experience it on my run.
It's a big shame 'cause that's basically (spoiler) only the half way point of the game... : /
There's a full 2nd half waiting....
In that case, I have an idea. Recently, I'm into troubleshooting game variables to do things like unlocking specific gallery scenes and explore game logic for fun. This plugin could help figure out what's going on: https://github.com/emerladCoder/RPG-Maker-MV-Cheat-Menu-Plugin.
The plugin adds dev console mode (F8) and game switches/variables (F9). F9 works and F8 is not loading on this game.
That said, this is coming from the player perspective. I'm not sure what it looks like from the developer perspective. I think rpgmaker is in Ruby?