Blender addon error when setting up collisions in a particular order

[Lamoot]

Here's another error popup bug. It occurs when custom properties are added in a particular order, starting with Set Collisions

Steps to reproduce:

1. Set Collisions
2. Set a path, here using material_0
3. Set Collisions again, a common action, when a user wants to edit and update the collisions

• The bug doesn't happen if a path was set before collisions were set.
• The bug happens if a custom property, not related to the addon, is added manually.
• Set Collisions still works as intended, the collision type is changed and values are properly updated. The error doesn't block the functionality at all.
• The bug stops appearing when collision is set to one of the types with a single property (mesh, simple, none).

Blender 4.2.3 and 2.4 version of the Blender addon.