Issue is caused by Game_Event having an instance variable containing a Sprite object. This Sprite is only created when the \msg[Name]
command is used in MCES.
Overall, the script is poorly designed and should be rewritten. I managed to at least remove the instance variable from Game_Event and have Sprite_Character be solely responsible for it, as it should.
For whatever reason, CP screams at me for a hacking attempt when posting the script, so pastebin link it is...https://pastebin.com/raw/zRqc9R0r