Collection was modified; enumeration operation may not execute

[MaksDragon]

Server is working, all was good. But one time map was save and i receive this error:
2022-02-21 21:23:03 - TShock: ERROR: System.InvalidOperationException: Collection was modified; enumeration operation may not execute.
at System.Collections.Generic.Dictionary`2+Enumerator[TKey,TValue].MoveNext () [0x00016] in <12b418a7818c4ca0893feeaaf67f1e7f>:0
at Terraria.GameContent.Bestiary.NPCKillsTracker.Save (System.IO.BinaryWriter writer) [0x00052] in <73ea76c09c3448288ab9a2ad67c342aa>:0
at Terraria.GameContent.Bestiary.BestiaryUnlocksTracker.Save (System.IO.BinaryWriter writer) [0x00000] in <73ea76c09c3448288ab9a2ad67c342aa>:0
at Terraria.IO.WorldFile.SaveBestiary (System.IO.BinaryWriter writer) [0x00000] in <73ea76c09c3448288ab9a2ad67c342aa>:0
at Terraria.IO.WorldFile.SaveWorld_Version2 (System.IO.BinaryWriter writer) [0x00059] in <73ea76c09c3448288ab9a2ad67c342aa>:0
at Terraria.IO.WorldFile.InternalSaveWorld (System.Boolean useCloudSaving, System.Boolean resetTime) [0x00055] in <73ea76c09c3448288ab9a2ad67c342aa>:0
at Terraria.IO.WorldFile+<>c__DisplayClass57_0.b__0 () [0x00000] in <73ea76c09c3448288ab9a2ad67c342aa>:0
at Terraria.Utilities.FileUtilities.ProtectedInvoke (System.Action action) [0x00016] in <73ea76c09c3448288ab9a2ad67c342aa>:0
at Terraria.IO.WorldFile.SaveWorldDirect (System.Boolean useCloudSaving, System.Boolean resetTime) [0x00066] in <73ea76c09c3448288ab9a2ad67c342aa>:0
at Terraria.IO.WorldFile.SaveWorld (System.Boolean useCloudSaving, System.Boolean resetTime) [0x00010] in <73ea76c09c3448288ab9a2ad67c342aa>:0
at Terraria.IO.WorldFile.SaveWorld () [0x00017] in <73ea76c09c3448288ab9a2ad67c342aa>:0
at Terraria.WorldGen.saveAndPlayCallBack (System.Object threadContext) [0x00000] in <73ea76c09c3448288ab9a2ad67c342aa>:0
at System.Threading.QueueUserWorkItemCallback.WaitCallback_Context (System.Object state) [0x0000e] in <12b418a7818c4ca0893feeaaf67f1e7f>:0
at System.Threading.ExecutionContext.RunInternal (System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, System.Object state, System.Boolean preserveSyncCtx) [0x0008d] in <12b418a7818c4ca0893feeaaf67f1e7f>:0
at System.Threading.ExecutionContext.Run (System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, System.Object state, System.Boolean preserveSyncCtx) [0x00000] in <12b418a7818c4ca0893feeaaf67f1e7f>:0
at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem () [0x0002a] in <12b418a7818c4ca0893feeaaf67f1e7f>:0
at System.Threading.ThreadPoolWorkQueue.Dispatch () [0x00096] in <12b418a7818c4ca0893feeaaf67f1e7f>:0
at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback () [0x00000] in <12b418a7818c4ca0893feeaaf67f1e7f>:0
2022-02-21 21:23:03 - Utils: INFO: Broadcast: Saving world...
2022-02-21 21:23:08 - Utils: INFO: Broadcast: World saved.
How i can fix that?

[hakusaro]

@MaksDragon fyi, we moved this to our new Terraria issue tracker. Re-Logic knows about this, but I don't know if they've patched it yet (cc @SignatureBeef).

[Kojirremer]

I've encountered that crash a noticeable amount of times in the past. I've yet to see it after the recent updates, though.