Server randomly crashes

[GCubeDude]

I'm pretty sure it's randomly happening when a player leaves the game.

java.lang.NullPointerException: Cannot invoke "it.unimi.dsi.fastutil.objects.ObjectSet.remove(Object)" because "$$4" is null
at knot//net.minecraft.class_3204.method_14051(class_3204.java:227)
at knot//net.minecraft.class_3898.method_18714(class_3898.java:1003)
at knot//net.minecraft.class_3898.method_18716(class_3898.java:1124)
at knot//net.minecraft.class_3215.method_18753(class_3215.java:463)
at knot//net.minecraft.class_3218$class_5526.method_31437(class_3218.java:1615)
at knot//net.minecraft.class_3218$class_5526.method_31797(class_3218.java:1570)
at knot//net.minecraft.class_5579.method_31850(class_5579.java:220)
at knot//net.minecraft.class_5579$class_5580.method_31750(class_5579.java:115)
at knot//dev.architectury.hooks.level.entity.fabric.EntityHooksImpl$1.method_31750(EntityHooksImpl.java:48)
at knot//net.minecraft.class_1297.method_31745(class_1297.java:3709)
at knot//net.minecraft.class_1297.method_5650(class_1297.java:415)
at knot//net.minecraft.class_1309.method_5650(class_1309.java:704)
at knot//net.minecraft.class_1657.method_5650(class_1657.java:1450)
at knot//net.minecraft.class_3218.method_18770(class_3218.java:953)
at knot//net.minecraft.class_3324.method_14611(class_3324.java:393)
at knot//net.minecraft.class_3244.method_52415(class_3244.java:1250)
at knot//net.minecraft.class_3244.method_10839(class_3244.java:1239)
at knot//net.minecraft.class_2535.method_10768(class_2535.java:673)
at knot//net.minecraft.class_3242.method_14357(class_3242.java:189)
at knot//net.minecraft.server.MinecraftServer.method_3813(MinecraftServer.java:1032)
at knot//net.minecraft.class_3176.method_3813(class_3176.java:299)
at knot//net.minecraft.server.MinecraftServer.method_3748(MinecraftServer.java:912)
at knot//net.minecraft.server.MinecraftServer.method_29741(MinecraftServer.java:697)
at knot//net.minecraft.server.MinecraftServer.method_29739(MinecraftServer.java:281)
at java.base/java.lang.Thread.run(Thread.java:1583)