BUG KeyNotFoundException in ProcessQueuedItems

[magiino]

I'm getting this exception from time to time.

Description: The process was terminated due to an unhandled exception.
Exception Info: System.Collections.Generic.KeyNotFoundException
   at System.Collections.Generic.Dictionary`2[[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]].get_Item(System.__Canon)
   at Amib.Threading.Internal.SynchronizedDictionary`2[[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]].get_Item(System.__Canon)
   at Amib.Threading.SmartThreadPool.ProcessQueuedItems()
   at System.Threading.ThreadHelper.ThreadStart_Context(System.Object)
   at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
   at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
   at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
   at System.Threading.ThreadHelper.ThreadStart()

17/3/2025
It looks like the thread is started on line 685 and added to the dictionary on line 689.

Fix: It must be added to the dictionary prior thread.Start() (line 685).

18/3/2025 UPDATE
I overlooked the lock, so my initial idea is a dead end.
I continue in the investigation.
Any ideas? Has anybody seen this error before?

Ssing SmarThreadPool in both .NET 8 and .NET Framework 4.8.
SmartThreadPool Version 2.3.0.
I will provide more info if you need it.

Thanks!