Trial Chambers Vaults become permanently inactive after updating world from 1.21.8 to 1.21.10/1.21.11

Expected behavior

Trial Chambers vaults should remain functional after server updates.
Players should be able to activate vaults using Trial Keys or Ominous Trial Keys as long as the chamber has not been completed, regardless of the server version upgrade.

Observed/Actual behavior

After updating the server version:

• Trial Chambers vaults are inactive and do not react to Trial Keys or Ominous Trial Keys.
• No errors appear in the server logs.
• The chambers appear visually intact, but vaults cannot be opened.
• Performing a WorldEdit //regen on the affected Trial Chamber fully restores correct behavior:
• Vaults become active again.
• Keys work as expected.

This indicates that the issue is related to persisted world / structure state rather than current game logic.

Steps/models to reproduce

1. Create a new world on Minecraft 1.21.8.
2. Generate one or more Trial Chambers naturally.
3. Update the server to Minecraft 1.21.10, then later to 1.21.11 (Paper).
4. Visit previously generated Trial Chambers.
5. Attempt to open vaults using Trial Keys or Ominous Trial Keys.
6. Observe that vaults do not activate.
7. Use WorldEdit //regen on the same Trial Chamber.
8. Observe that vaults work correctly after regeneration.

Plugin and Datapack List

AdvancedCrates, AxAuctions, AxGraves, AxPlayerWarps, AxRewards, AxTrade, AxVaults, ChatControl, CMI, CMIEInjector
CMILib, ConsoleFilter, CoreProtect, DeluxeMenus, DonutWorth, EntityLimiter, fairy-lib-plugin, FastAsyncWorldEdit, GrimAC, GSit
LuckPerms, Multiverse-Core, PlaceholderAPI, PlayerPoints, ProtocolLib, pvparena, raytraced-antixray
raytraced-tile-culling, RedstoneLimiter, SkinsRestorer, TAB, TNTRun_reloaded, TreeCuter, Vault, ViaBackwards, ViaVersion, voicechat
VoidGen, WGExtender, WorldEditSelectionVisualizer, WorldGuard, WorldGuardExtraFlags, ZelTeams

There are 3 data pack(s) enabled: [vanilla (built-in)], [file/bukkit (world)], [paper (built-in)]
There are no more data packs available

Paper version

This server is running Paper version 1.21.11-88-main@8556cb4 (2026-01-05T09:39:44Z) (Implementing API version 1.21.11-R0.1-SNAPSHOT)
You are running the latest version
Previous version: 1.21.11-2553-5b4cbcc (MC: 1.21.11)

Other

This issue affects only Trial Chambers generated before the version updates.

Newly regenerated chambers function correctly.

The issue appears to be caused by persisted Trial Chamber / Vault state saved in chunks and not migrated or revalidated during version upgrades.

This behavior is reproducible and does not depend on specific player actions.

No source files or tests are named. Start by reproducing the upgrade path from Minecraft 1.21.8 to Paper 1.21.10 or 1.21.11, then compare persisted vault and Trial Chamber state with a regenerated chamber. Done means affected existing vaults can activate with the appropriate keys after upgrading, without requiring WorldEdit regeneration, and regression coverage protects the migration path.