Error in console: https://pastebin.com/2b64BBRF

When a player places/breaks a skull of an offline player, it will lag the server down to 2 tps and flare the above error.

Version:

.... [16:27:22 INFO]: Server version: 1.16.1-R0.1-SNAPSHOT git-Tuinity-"489faf0" (MC: 1.16.1)
.... [16:27:22 INFO]: EssentialsX version: 2.18.0.7
.... [16:27:22 INFO]: PlaceholderAPI version: 2.10.7
.... [16:27:22 INFO]: LuckPerms version: 5.1.26
.... [16:27:22 INFO]: Vault version: 1.7.3-b131
.... [16:27:22 INFO]: Citizens version: 2.0.27-SNAPSHOT (build 2019)
.... [16:27:22 INFO]: EssentialsXChat version: 2.18.0.7
.... [16:27:22 INFO]: EssentialsXSpawn version: 2.18.0.7
.... [16:27:22 INFO]: ChestShop version: 3.11.1-SNAPSHOT (build 224)

Removing Protection Stones worked.