[Bug]: Level.spawn() function doesn't work after using a door

[Eauix]

SuperTux Version

SuperTux-v0.6.3-1251-g1fa2a76c8

System Information

Windows 10, 64bit

Expected Behavior

The spawning function works in any normal circumstances

Actual Behavior

If you enter a door in your level, the spawning function will no longer work in the level until you exit and enter the level again (restarting the level doesn't solve the problem)

https://github.com/SuperTux/supertux/assets/145238217/9c0fe420-b96e-422b-9f51-c44c9697ac4f

Steps To Reproduce Actual Behavior

1. Place a door that leads to any spawnpoint
2. Place a script trigger or a switch with a Level.spawn() function that leads to any spawnpoint
3. Use the switch to go to its destination
4. Use the door to go to its destination
5. Use the switch again, it will not do anything

Additional Information

No response

Guidelines For Reporting Issues

• [X] I have read https://github.com/SuperTux/supertux/blob/master/CONTRIBUTING.md#bug-reports.
• [X] I have verified this isn't an issue that's already been reported.
• [X] I have verified this isn't a discussion, or an issue about a crash or a feature request, but rather an actual bug ─ that is, the game did something not intended.
• [X] I have verified this issue is not about wrong translations (use Transifex for those), or anything unsupported (e.g. third-party add-ons).
• [X] In this report, I have only included details about one (1) bug.
• [X] If I make a mistake while submitting this report, I agree to use the "Edit" feature to correct it, instead of closing this issue and opening a new one.