I had the same issue after updating from 0.16 to 0.17. I had to copy latest save file from 0.17, load it in 0.16, trigger the event, then copy save file back to 0.17
I don't know how to fix it if you don't have 0.16 though (I had backup just in case)
Edit: seems like someone posted solution about changing variable "store.nia_alert00" a little below, so you should probably take a look
First, make a backup of your save
From what I googled, you will need a Ren'py save editor
Open the savefile with it and find the variable "store.nia_alert00"
Change it to false
Save the changes and try loading that save
You might have to do that process again, but set the variable to true after triggering the event
I haven't tried this yet, but I will let you know when I do
This site has some options for save editors. Again, I haven't tested myself yet
https://arceusx.net/renpy-save-editor/#What_Ren’Py_Save_Editor_Is_Used_For
Can confirm it works, Just follow the instructions above.
I used this site to edit the save
https://www.saveeditonline.com/
The variable I edited was "nia_alert00"
changed the value from 1 to 0
After finishing the event 31 I changed it back to 1
Hope it helps!
