Players sometimes die in some areas that trigger this bug causing the server to crash.Not just a particular player,every player has the opportunity to trigger the bug...I will paste my crashed-report below.Thanks for reading.

Error message for the console and the crashed-report file:

[19:43:44] [Server thread/ERROR]: Encountered an unexpected exception
net.minecraft.ReportedException: Ticking entity
    at net.minecraft.server.MinecraftServer.c(MinecraftServer.java:1478) ~[spigot-1.21-R0.1-SNAPSHOT.jar:4288-Spigot-fb8fb72-8f26c30]
    at net.minecraft.server.dedicated.DedicatedServer.c(DedicatedServer.java:406) ~[spigot-1.21-R0.1-SNAPSHOT.jar:4288-Spigot-fb8fb72-8f26c30]
    at net.minecraft.server.MinecraftServer.a(MinecraftServer.java:1321) ~[spigot-1.21-R0.1-SNAPSHOT.jar:4288-Spigot-fb8fb72-8f26c30]
    at net.minecraft.server.MinecraftServer.y(MinecraftServer.java:1071) ~[spigot-1.21-R0.1-SNAPSHOT.jar:4288-Spigot-fb8fb72-8f26c30]
    at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:318) ~[spigot-1.21-R0.1-SNAPSHOT.jar:4288-Spigot-fb8fb72-8f26c30]
    at java.base/java.lang.Thread.run(Thread.java:1583) [?:?]
Caused by: java.lang.UnsupportedOperationException
    at java.base/java.util.ImmutableCollections.uoe(ImmutableCollections.java:142) ~[?:?]
    at java.base/java.util.ImmutableCollections$AbstractImmutableCollection.clear(ImmutableCollections.java:149) ~[?:?]
    at net.minecraft.server.network.PlayerConnection.teleport(PlayerConnection.java:1398) ~[spigot-1.21-R0.1-SNAPSHOT.jar:4288-Spigot-fb8fb72-8f26c30]
    at net.minecraft.server.level.EntityPlayer.teleportTo(EntityPlayer.java:1936) ~[spigot-1.21-R0.1-SNAPSHOT.jar:4288-Spigot-fb8fb72-8f26c30]
    at net.minecraft.server.level.EntityPlayer.d(EntityPlayer.java:2139) ~[spigot-1.21-R0.1-SNAPSHOT.jar:4288-Spigot-fb8fb72-8f26c30]
    at net.minecraft.server.level.EntityPlayer.l(EntityPlayer.java:709) ~[spigot-1.21-R0.1-SNAPSHOT.jar:4288-Spigot-fb8fb72-8f26c30]
    at net.minecraft.server.level.WorldServer.a(WorldServer.java:889) ~[spigot-1.21-R0.1-SNAPSHOT.jar:4288-Spigot-fb8fb72-8f26c30]
    at net.minecraft.world.level.World.a(World.java:684) ~[spigot-1.21-R0.1-SNAPSHOT.jar:4288-Spigot-fb8fb72-8f26c30]
    at net.minecraft.server.level.WorldServer.lambda$tick$2(WorldServer.java:459) ~[spigot-1.21-R0.1-SNAPSHOT.jar:4288-Spigot-fb8fb72-8f26c30]
    at net.minecraft.world.level.entity.EntityTickList.a(SourceFile:54) ~[spigot-1.21-R0.1-SNAPSHOT.jar:4288-Spigot-fb8fb72-8f26c30]
    at net.minecraft.server.level.WorldServer.a(WorldServer.java:439) ~[spigot-1.21-R0.1-SNAPSHOT.jar:4288-Spigot-fb8fb72-8f26c30]
    at net.minecraft.server.MinecraftServer.c(MinecraftServer.java:1472) ~[spigot-1.21-R0.1-SNAPSHOT.jar:4288-Spigot-fb8fb72-8f26c30]
    ... 5 more
[19:43:44] [Server thread/ERROR]: This crash report has been saved to: D:\server1.21\crash-reports\crash-2024-08-16_19.43.44-server.txt
[19:43:44] [Server thread/INFO]: Stopping server