Package error only when BP has Nativize ticked

I’m trying to package my project with selective Nativization and it works with the first two BP’s I selected to do it for.
But for the third of my slower BP’s I get a crash when packaging while having Nativization enabled. It doesn’t crash if I don’t include this BP and it also doesn’t crash when I package without Nativization on.

I think this part of the Output Log has something to do with it,



LogInit:Display: LogOutputDevice:Error: Ensure condition failed: FunctionReference.IsSelfContext() || (MemberClass != nullptr) || bIsLocalMacro [File:D:\Build\++UE4+Release-4.16+Compile\Sync\Engine\Source\Editor\BlueprintGraph\Private\K2Node_CallFunction.cpp] [Line: 1701]
LogInit:Display: LogOutputDevice:Error: Unknown member class in /Temp/__TEMP_BP__/Game/Avatar/Avatar_Pawn.Avatar_Pawn:EventGraph.K2Node_CallFunction_12161
LogInit:Display: LogOutputDevice:Error: Stack: 
LogInit:Display: LogOutputDevice:Error: UE4Editor-Core.dll!0x000000006EDBE1C6
LogInit:Display: LogOutputDevice:Error: UE4Editor-Core.dll!0x000000006EB6B7D2
LogInit:Display: LogOutputDevice:Error: UE4Editor-Core.dll!0x000000006EB81D96
LogInit:Display: LogOutputDevice:Error: UE4Editor-BlueprintGraph.dll!0x000000006923ECC6
LogInit:Display: LogOutputDevice:Error: UE4Editor-BlueprintGraph.dll!0x0000000069259470
LogInit:Display: LogOutputDevice:Error: UE4Editor-CoreUObject.dll!0x000000006E723CA8
LogInit:Display: LogOutputDevice:Error: UE4Editor-CoreUObject.dll!0x000000006E722E26
LogInit:Display: LogOutputDevice:Error: UE4Editor-BlueprintNativeCodeGen.dll!0x000000006304A520
LogInit:Display: LogOutputDevice:Error: UE4Editor-BlueprintNativeCodeGen.dll!0x000000006304D9DB
LogInit:Display: LogOutputDevice:Error: UE4Editor-BlueprintNativeCodeGen.dll!0x000000006304B3D4
LogInit:Display: LogOutputDevice:Error: UE4Editor-UnrealEd.dll!0x000000006C6663D7
LogInit:Display: LogOutputDevice:Error: UE4Editor-UnrealEd.dll!0x000000006C6C941D
LogInit:Display: LogOutputDevice:Error: UE4Editor-UnrealEd.dll!0x000000006C576D72
LogInit:Display: LogOutputDevice:Error: UE4Editor-UnrealEd.dll!0x000000006C59BA21
LogInit:Display: LogOutputDevice:Error: UE4Editor-Cmd.exe!0x0000000027197B8F
LogInit:Display: LogOutputDevice:Error: UE4Editor-Cmd.exe!0x000000002718EEDA
LogInit:Display: LogOutputDevice:Error: UE4Editor-Cmd.exe!0x000000002718F12A
LogInit:Display: LogOutputDevice:Error: UE4Editor-Cmd.exe!0x00000000271A0CF9
LogInit:Display: LogOutputDevice:Error: UE4Editor-Cmd.exe!0x00000000271A1A1F
LogInit:Display: LogOutputDevice:Error: KERNEL32.DLL!0x00000000A8C213D2
LogInit:Display: LogOutputDevice:Error: ntdll.dll!0x00000000AB2B54E4
LogInit:Display: LogOutputDevice:Error: end: stack for UAT

How can I identify where in my rather expansive BP this could come from?

Cheers