Failed to convert json to nbt

[Schneidertm]

Stack trace

https://mclo.gs/XtdkdPx

Plugin and Datapack List

Paper Plugins (4):
CraftBook5, HuskHomes, LiteEco
Bukkit Plugins (31):
ChunkSpawnerLimiter, Chunky, ColoredSigns, CommandBook, DiscordSRV, FarmControl, FlyingCarpet, LogBlock, LogBlockQuestioner, LuckPerms, LWC, mcMMO, Multiverse-Core, Multiverse-Portals, OpenInv, ProtocolLib, QuickShop-Hikari, RedstoneClockDetector, SignRewards, TitleManager, VanishNoPacket, Vault, VaultChatFormatter, ViaVersion, Votifier, WorldBorder, WorldEdit, WorldGuard, ZHorse

Actions to reproduce (if known)

No response

Paper version

This server is running Paper version 1.21.6-46-main@35b2c6e (2025-06-26T18:53:41Z) (Implementing API version 1.21.6-R0.1-SNAPSHOT)

Other

I haven't done force-upgrade recently. Not sure when last but it should be a few major versions ago.

[Spottedleaf]

All DataConverter is doing here is logging, I don't see how it crashed anything.

I need data to look at this further, but just by looking at the logs it looks like it just encountered invalid data. I don't think any of these would have loaded on 1.21.4.

[Schneidertm]

Thank you for looking into! I'm sorry its not a crash, its only display when there is a crash by 3rd parties.

[TZ122]

I seem to be having a similar issue when upgrading from 1.21.1 -> 1.21.8 latest paper.
I also tried 1.21.1 -> 1.21.4 -> 1.21.8

Here is the log: https://mclo.gs/E128mNZ

Is there anything I can do in the interim? The server doesn't crash, but the error spams infinitely.

[tommy10606]

Issue 12873 on the PaperMC/Paper github was created. These errors make reading the console almost impossible during boot and whenever a player's inventory is read that has a problematic item.

[tommy10606]

It looks like bug #25 is related as well.