Null Pointer exception in "player tracker clear"

[passed-prime]

[EDIT] Issue is a bit more problematic... It seems that on Bedrock clients the model isn't viewable. In this instance I am using the ResurrectionChest plugin's custom model and it is not visible. Instead it shows the armor stand and interferes with the chest's functionality as well.

There's an error that's pretty noisy and spammy that hits my server logs repeatedly... I'm worried it might be some kind of memory leak/repeating problem. I'm gonna take a deeper dive on this one but I thought I'd post it here for others that may have the same issue:

[16:04:07 ERROR]: Thread Craft Scheduler Thread - 25 - FreeMinecraftModels failed main thread check: player tracker clear
java.lang.Throwable: null
        at org.spigotmc.AsyncCatcher.catchOp(AsyncCatcher.java:9) ~[paper-1.21.8.jar:1.21.8-60-29c8822]
        at net.minecraft.server.level.ChunkMap$TrackedEntity.removePlayer(ChunkMap.java:1275) ~[paper-1.21.8.jar:1.21.8-60-29c8822]
        at org.bukkit.craftbukkit.entity.CraftPlayer.unregisterEntity(CraftPlayer.java:2032) ~[paper-1.21.8.jar:1.21.8-60-29c8822]
        at org.bukkit.craftbukkit.entity.CraftPlayer.untrackAndHideEntity(CraftPlayer.java:2023) ~[paper-1.21.8.jar:1.21.8-60-29c8822]
        at org.bukkit.craftbukkit.entity.CraftPlayer.hideEntity0(CraftPlayer.java:2000) ~[paper-1.21.8.jar:1.21.8-60-29c8822]
        at org.bukkit.craftbukkit.entity.CraftPlayer.hideEntity(CraftPlayer.java:1984) ~[paper-1.21.8.jar:1.21.8-60-29c8822]
        at FreeMinecraftModels.jar/com.magmaguy.freeminecraftmodels.customentity.core.SkeletonWatchers.hideFrom(SkeletonWatchers.java:240) ~[FreeMinecraftModels.jar:?]
        at FreeMinecraftModels.jar/com.magmaguy.freeminecraftmodels.customentity.core.SkeletonWatchers.lambda$resync$0(SkeletonWatchers.java:76) ~[FreeMinecraftModels.jar:?]
        at java.base/java.lang.Iterable.forEach(Iterable.java:75) ~[?:?]
        at java.base/java.util.Collections$SynchronizedCollection.forEach(Collections.java:2351) ~[?:?]
        at FreeMinecraftModels.jar/com.magmaguy.freeminecraftmodels.customentity.core.SkeletonWatchers.resync(SkeletonWatchers.java:75) ~[FreeMinecraftModels.jar:?]
        at FreeMinecraftModels.jar/com.magmaguy.freeminecraftmodels.customentity.core.SkeletonWatchers.tick(SkeletonWatchers.java:52) ~[FreeMinecraftModels.jar:?]
        at FreeMinecraftModels.jar/com.magmaguy.freeminecraftmodels.customentity.core.Skeleton.tick(Skeleton.java:97) ~[FreeMinecraftModels.jar:?]
        at FreeMinecraftModels.jar/com.magmaguy.freeminecraftmodels.customentity.ModeledEntity.tick(ModeledEntity.java:171) ~[FreeMinecraftModels.jar:?]
        at FreeMinecraftModels.jar/com.magmaguy.freeminecraftmodels.customentity.ModeledEntitiesClock.lambda$tick$0(ModeledEntitiesClock.java:30) ~[FreeMinecraftModels.jar:?]
        at java.base/java.util.concurrent.ConcurrentHashMap$KeySetView.forEach(ConcurrentHashMap.java:4709) ~[?:?]
        at FreeMinecraftModels.jar/com.magmaguy.freeminecraftmodels.customentity.ModeledEntitiesClock.tick(ModeledEntitiesClock.java:30) ~[FreeMinecraftModels.jar:?]
        at FreeMinecraftModels.jar/com.magmaguy.freeminecraftmodels.customentity.ModeledEntitiesClock$1.run(ModeledEntitiesClock.java:19) ~[FreeMinecraftModels.jar:?]
        at org.bukkit.craftbukkit.scheduler.CraftTask.run(CraftTask.java:78) ~[paper-1.21.8.jar:1.21.8-60-29c8822]
        at org.bukkit.craftbukkit.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:57) ~[paper-1.21.8.jar:1.21.8-60-29c8822]
        at com.destroystokyo.paper.ServerSchedulerReportingWrapper.run(ServerSchedulerReportingWrapper.java:22) ~[paper-1.21.8.jar:?]
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144) ~[?:?]
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642) ~[?:?]
        at java.base/java.lang.Thread.run(Thread.java:1583) ~[?:?]
[16:04:24 WARN]: [FreeMinecraftModels] Plugin FreeMinecraftModels v2.3.11 generated an exception while executing task 4213
java.lang.IllegalStateException: Asynchronous player tracker clear!
        at org.spigotmc.AsyncCatcher.catchOp(AsyncCatcher.java:10) ~[paper-1.21.8.jar:1.21.8-60-29c8822]
        at net.minecraft.server.level.ChunkMap$TrackedEntity.removePlayer(ChunkMap.java:1275) ~[paper-1.21.8.jar:1.21.8-60-29c8822]
        at org.bukkit.craftbukkit.entity.CraftPlayer.unregisterEntity(CraftPlayer.java:2032) ~[paper-1.21.8.jar:1.21.8-60-29c8822]
        at org.bukkit.craftbukkit.entity.CraftPlayer.untrackAndHideEntity(CraftPlayer.java:2023) ~[paper-1.21.8.jar:1.21.8-60-29c8822]
        at org.bukkit.craftbukkit.entity.CraftPlayer.hideEntity0(CraftPlayer.java:2000) ~[paper-1.21.8.jar:1.21.8-60-29c8822]
        at org.bukkit.craftbukkit.entity.CraftPlayer.hideEntity(CraftPlayer.java:1984) ~[paper-1.21.8.jar:1.21.8-60-29c8822]
        at FreeMinecraftModels.jar/com.magmaguy.freeminecraftmodels.customentity.core.SkeletonWatchers.hideFrom(SkeletonWatchers.java:240) ~[FreeMinecraftModels.jar:?]
        at java.base/java.util.ArrayList.forEach(ArrayList.java:1596) ~[?:?]
        at FreeMinecraftModels.jar/com.magmaguy.freeminecraftmodels.customentity.core.SkeletonWatchers.updateWatcherList(SkeletonWatchers.java:116) ~[FreeMinecraftModels.jar:?]
        at FreeMinecraftModels.jar/com.magmaguy.freeminecraftmodels.customentity.core.SkeletonWatchers.tick(SkeletonWatchers.java:49) ~[FreeMinecraftModels.jar:?]
        at FreeMinecraftModels.jar/com.magmaguy.freeminecraftmodels.customentity.core.Skeleton.tick(Skeleton.java:97) ~[FreeMinecraftModels.jar:?]
        at FreeMinecraftModels.jar/com.magmaguy.freeminecraftmodels.customentity.ModeledEntity.tick(ModeledEntity.java:171) ~[FreeMinecraftModels.jar:?]
        at FreeMinecraftModels.jar/com.magmaguy.freeminecraftmodels.customentity.ModeledEntitiesClock.lambda$tick$0(ModeledEntitiesClock.java:30) ~[FreeMinecraftModels.jar:?]
        at java.base/java.util.concurrent.ConcurrentHashMap$KeySetView.forEach(ConcurrentHashMap.java:4709) ~[?:?]
        at FreeMinecraftModels.jar/com.magmaguy.freeminecraftmodels.customentity.ModeledEntitiesClock.tick(ModeledEntitiesClock.java:30) ~[FreeMinecraftModels.jar:?]
        at FreeMinecraftModels.jar/com.magmaguy.freeminecraftmodels.customentity.ModeledEntitiesClock$1.run(ModeledEntitiesClock.java:19) ~[FreeMinecraftModels.jar:?]
        at org.bukkit.craftbukkit.scheduler.CraftTask.run(CraftTask.java:78) ~[paper-1.21.8.jar:1.21.8-60-29c8822]
        at org.bukkit.craftbukkit.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:57) ~[paper-1.21.8.jar:1.21.8-60-29c8822]
        at com.destroystokyo.paper.ServerSchedulerReportingWrapper.run(ServerSchedulerReportingWrapper.java:22) ~[paper-1.21.8.jar:?]
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144) ~[?:?]
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642) ~[?:?]
        at java.base/java.lang.Thread.run(Thread.java:1583) ~[?:?]

[passed-prime]

Very odd. There must be some sort of race condition in https://github.com/MagmaGuy/FreeMinecraftModels/blob/master/src/main/java/com/magmaguy/freeminecraftmodels/customentity/core/SkeletonWatchers.java#L240C55-L240C104 , but it already seems to perform a null check on the entity.