*Steps to reproduce:*
# Create and open an empty project.
# Download and add the attached component 'TestClass.cs' to a game object.
# Add 2 or more items to the 'Unity Event ()' serialized property of the Test Class component.
# Remove all the items.
# Add the items again.
# Remove the items again.

*Actual results:* Several errors are thrown in the console and the items don't get removed properly.

*Expected results:* No errors are thrown and an item is removed when you press the minus button.

*Reproducible with versions:* 
6000.0.5f1
2023.2.0a10

*Not reproducible with versions:* 
2022.3.29f1
2021.3.38f1

*Tested on (OS):* MacOS (M1) 14.4.1