User Message: An unhandled exception has occurred. You can continue running PKHeX, but please report this error.

[XdeadReaper]

Exception Details:
System.IndexOutOfRangeException: Index was outside the bounds of the array.
   at System.ThrowHelper.ThrowIndexOutOfRangeException()
   at PKHeX.Core.LearnSource2GS.GetAllMoves(Span`1 result, PKM pk, EvoCriteria evo, MoveSourceType types)
   at PKHeX.Core.LearnGroup2.GetAllMoves(Span`1 result, PKM pk, EvoCriteria evo, MoveSourceType types)
   at PKHeX.Core.LearnGroup2.GetAllMoves(Span`1 result, PKM pk, EvolutionHistory history, IEncounterTemplate enc, MoveSourceType types, LearnOption option)
   at PKHeX.Core.LearnPossible.IterateAndFlag(Span`1 result, PKM pk, IEncounterTemplate enc, EvolutionHistory history, MoveSourceType types)
   at PKHeX.Core.EncounterMovesetGenerator.GetNeededMoves(PKM pk, ReadOnlySpan`1 moves)
   at PKHeX.Core.EncounterMovesetGenerator.GenerateVersionEncounters(PKM pk, UInt16[] moves, GameVersion version)
   at PKHeX.Core.EncounterMovesetGenerator.<GenerateEncounters>d__10.MoveNext()
   at PKHeX.WinForms.SAV_Encounters.<GetAllSpeciesFormEncounters>d__23.MoveNext()
   at System.Linq.Enumerable.<DistinctIterator>d__64`1.MoveNext()
   at System.Linq.Enumerable.WhereEnumerableIterator`1.MoveNext()
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at System.Threading.Tasks.Task`1.InnerInvoke()
   at System.Threading.Tasks.Task.Execute()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at PKHeX.WinForms.SAV_Encounters.<B_Search_Click>d__27.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()

Loaded Assemblies:
--------------------
mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\mscorlib.dll

PKHeX, Version=22.8.31.0, Culture=neutral, PublicKeyToken=null
C:\Users\marti\Downloads\PKHeX (220831)\PKHeX.exe

System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System\v4.0_4.0.0.0__b77a5c561934e089\System.dll

System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Windows.Forms\v4.0_4.0.0.0__b77a5c561934e089\System.Windows.Forms.dll

System.Drawing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Drawing\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Drawing.dll

System.Configuration, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Configuration\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Configuration.dll

System.Core, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Core\v4.0_4.0.0.0__b77a5c561934e089\System.Core.dll

System.Xml, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Xml\v4.0_4.0.0.0__b77a5c561934e089\System.Xml.dll

PKHeX.Core, Version=22.6.26.0, Culture=neutral, PublicKeyToken=null

PKHeX.Core, Version=22.6.26.0, Culture=neutral, PublicKeyToken=null

System.Memory, Version=4.0.1.1, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51

System.Memory, Version=4.0.1.1, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51

System.Runtime, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Runtime\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Runtime.dll

System.Runtime.CompilerServices.Unsafe, Version=4.0.4.1, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a

System.Runtime.InteropServices, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Runtime.InteropServices\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Runtime.InteropServices.dll

System.Reflection, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Reflection\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Reflection.dll

System.Runtime.Extensions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Runtime.Extensions\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Runtime.Extensions.dll

Newtonsoft.Json, Version=13.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed

PKHeX.Drawing.PokeSprite, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null

System.ValueTuple, Version=4.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.ValueTuple\v4.0_4.0.0.0__cc7b13ffcd2ddd51\System.ValueTuple.dll

PKHeX.Drawing, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null

System.Buffers, Version=4.0.3.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51

System.Threading, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Threading\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Threading.dll

System.Diagnostics.Debug, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Diagnostics.Debug\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Diagnostics.Debug.dll

System.Diagnostics.Tracing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Diagnostics.Tracing\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Diagnostics.Tracing.dll

PKHeX.Drawing.Misc, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null

Accessibility, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\Accessibility\v4.0_4.0.0.0__b03f5f7f11d50a3a\Accessibility.dll

--------------------
User Message:
An unhandled exception has occurred.
You can continue running PKHeX, but please report this error.
 

[Kaphotics]

Please indicate the steps to replicate, it is not clear from the stacktrace what inputs you used to trigger the message.

edit: fixed on latest dev build! thanks for reporting