[MU4 Issue] Instance-specific crash when closing a score containing a missing instance of Kontakt

[bkunda]

Describe the bug See demo video (My apologies, it's pretty boring): https://www.dropbox.com/s/3g3r2n8zd0jgka1/Screen%20Recording%202023-01-13%20at%2012.46.45%20pm.mov?dl=0

This is the score I was able to reproduce the issue with: [Uploading The_Griggles (2).mscz.zip…](Original file containing Kontakt instance)

In short:

• Open the above score
• Wait for audio samples to load
• See message stating that an instance of Kontakt couldn't be loaded
• Press Cmd+W
• This instance of MuseScore crashes (At least 3-4 times). Other instances remain open and unaffected

Then

• Re-open this file
• Wait for audio samples to load
• Replace Kontakt instrument with something else (I used MuseSounds grand piano)
• Press Cmd+W
• Save dialog is triggered. Press Save
• Instance crashes
• Re-open instance, and close it again. No more crashes.

Platform information

• OS: macOS 12.6 (M1)

@Tantacrul FYI