Crash on open level (100%): Assertion Failed

I am at wit’s end. 5 years’ worth of work. Now the game is in limbo, as I cannot even open some levels. The levels I try to open also haven’t been in touch for at least weeks.

LoginId:5ecd60804f42f39989a1b8b2c6616e3a
EpicAccountId:c3d30a5fffd0429daebbb99aac7c1f4f

Assertion failed: NumNewPins == InNewPins.Num() [File:D:/Build/++UE4/Sync/Engine/Source/Editor/BlueprintGraph/Private/K2Node.cpp] [Line: 1104]

UE4Editor_Core
UE4Editor_Core
UE4Editor_BlueprintGraph
UE4Editor_BlueprintGraph
UE4Editor_BlueprintGraph
UE4Editor_UnrealEd
UE4Editor_Kismet
UE4Editor_Kismet
UE4Editor_CoreUObject
UE4Editor_CoreUObject
UE4Editor_CoreUObject
UE4Editor_CoreUObject
UE4Editor_CoreUObject
UE4Editor_CoreUObject
UE4Editor_CoreUObject
UE4Editor_CoreUObject
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor_ContentBrowser
UE4Editor_ContentBrowser
UE4Editor_ContentBrowser
UE4Editor_ContentBrowser
UE4Editor_ContentBrowser
UE4Editor_ContentBrowser
UE4Editor_ContentBrowser
UE4Editor_ContentBrowser
UE4Editor_ContentBrowser
UE4Editor_Slate
UE4Editor_Slate
UE4Editor_Slate
UE4Editor_Slate
UE4Editor_ApplicationCore
UE4Editor_ApplicationCore
UE4Editor_ApplicationCore
UE4Editor_ApplicationCore
user32
user32
UE4Editor_ApplicationCore
UE4Editor
UE4Editor
UE4Editor
UE4Editor
UE4Editor
kernel32
ntdll

Hello! Can you attach full log? And what about version control?