I'm so glad that you can fix it smoothly. But for safety, I think you should keep the backup of a saved file that is before you manually fix the festival too in case there are hidden bugs from manual deleting with mods.
I also fixed my university world lots by changing lot types to reset uni-club events. But I got "Last Exception" every time I did it. So, I still am not sure if I did it right even though I did it without using mods.
This game is too dangerous for long-term playing save. Be aware in any case. 😂