SlimeWorld PDC not saving

[Wupin]

Describe the issue
PDC of SlimeWorlds does not persist after a server restart. When storing PDC data in a Bukkit world via SlimeWorldInstance#getBukkitWorld(), it saves correctly. However, when setting PDC directly on the SlimeWorldInstance using getPersistentDataContainer().set(...), the data is lost after saving and reloading the world.

Spigot version
This server is running AdvancedSlimePaper version 1.21.8-16724-develop@39ec52c (2025-07-26T23:28:27Z) (Implementing API version 1.21.8-R0.1-SNAPSHOT)
You are running the latest version
Previous version: 1.21.8-28-8010812 (MC: 1.21.8)

Plugin version
none

How to reproduce

1. Store some data in the SlimeWorld's PDC via SlimeWorldInstance#getPersistentDataContainer().set(...)
2. Save the world
3. Load the world again
4. The previously stored PDC data will be missing

Crash reports (if available)
none