iOS Unload crash

[Kevadroz]

Describe the bug
Sometimes when the persistent checkpoints unload the game crashes

To Reproduce
Steps to reproduce the behavior:

1. Place some persistent checkpoints in a level (like 5, 6 or more)
2. Unload the checkpoints (close the level)
3. Crash

Expected behavior
No crash

Setup info

• Platform: iOS
• Mod Version: 1.4.0-beta
• Geode version: 5.3.0
• Dependencies:
  • PersistenceAPI: 1.2.0-beta
  • NodeIDs: idk

Additional context
Reported by elniel on Discord