A crash occured on my server whilst my players were playing.

Crashlog:
crash-2021-09-28_02.06.55-server.txt

---- Minecraft Crash Report ----
// I just don't know what went wrong :(

Time: 9/28/21 2:06 AM
Description: Exception in server tick loop

java.util.ConcurrentModificationException: null
at java.util.HashMap$HashIterator.nextNode(HashMap.java:1445) ~[?:1.8.0_282] {}
at java.util.HashMap$ValueIterator.next(HashMap.java:1474) ~[?:1.8.0_282] {}
at de.ellpeck.craftabledeeds.DeedStorage.update(DeedStorage.java:64) ~[craftabledeeds:2.2] {re:mixin,re:classloading}
at de.ellpeck.craftabledeeds.Events.onWorldTick(Events.java:68) ~[craftabledeeds:2.2] {re:classloading}
at net.minecraftforge.eventbus.ASMEventHandler_871_Events_onWorldTick_WorldTickEvent.invoke(.dynamic) ~[?:?] {}
at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:85) ~[eventbus-4.0.0.jar:?] {}
at net.minecraftforge.eventbus.EventBus.post(EventBus.java:302) ~[eventbus-4.0.0.jar:?] {}
at net.minecraftforge.eventbus.EventBus.post(EventBus.java:283) ~[eventbus-4.0.0.jar:?] {}
at net.minecraftforge.fml.hooks.BasicEventHooks.onPostWorldTick(BasicEventHooks.java:100) ~[forge:?] {re:classloading}
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:857) ~[?:?] {re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:classloading,pl:accesstransformer:B,pl:mixin:APP:structure_gel.mixins.json:MinecraftServerMixin,pl:mixin:APP:globaldataandresourcepacks.mixins.json:MinecraftServerMixin,pl:mixin:APP:byg.mixins.json:server.MixinMinecraftServer,pl:mixin:APP:mixin.terraforged.json:common.MixinMinecraftServer,pl:mixin:A,pl:runtimedistcleaner:A}
at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:291) ~[?:?] {re:classloading,pl:accesstransformer:B}
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:787) ~[?:?] {re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:classloading,pl:accesstransformer:B,pl:mixin:APP:structure_gel.mixins.json:MinecraftServerMixin,pl:mixin:APP:globaldataandresourcepacks.mixins.json:MinecraftServerMixin,pl:mixin:APP:byg.mixins.json:server.MixinMinecraftServer,pl:mixin:APP:mixin.terraforged.json:common.MixinMinecraftServer,pl:mixin:A,pl:runtimedistcleaner:A}
at net.minecraft.server.MinecraftServer.func_240802_v_(MinecraftServer.java:642) ~[?:?] {re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:classloading,pl:accesstransformer:B,pl:mixin:APP:structure_gel.mixins.json:MinecraftServerMixin,pl:mixin:APP:globaldataandresourcepacks.mixins.json:MinecraftServerMixin,pl:mixin:APP:byg.mixins.json:server.MixinMinecraftServer,pl:mixin:APP:mixin.terraforged.json:common.MixinMinecraftServer,pl:mixin:A,pl:runtimedistcleaner:A}
at net.minecraft.server.MinecraftServer.func_240783_a_(MinecraftServer.java:232) ~[?:?] {re:mixin,pl:accesstransformer:B,pl:runtimedistcleaner:A,re:classloading,pl:accesstransformer:B,pl:mixin:APP:structure_gel.mixins.json:MinecraftServerMixin,pl:mixin:APP:globaldataandresourcepacks.mixins.json:MinecraftServerMixin,pl:mixin:APP:byg.mixins.json:server.MixinMinecraftServer,pl:mixin:APP:mixin.terraforged.json:common.MixinMinecraftServer,pl:mixin:A,pl:runtimedistcleaner:A}
at java.lang.Thread.run(Thread.java:748) [?:1.8.0_282] {}