Hi all,
I did a quick google for “Assertion failed: NumBytes == Strings.Num() [File:D:/Build/++UE4/Sync/Engine/Source/Runtime/Core/Private/UObject/UnrealNames.cpp] [Line: 3336]” and came across this thread.
Advice is to delete C:\Users\username\AppData\Local\UnrealEngine\5.0\Intermediate
(You can also delete saved/intermediate folders in your projects and they will be regenerated on project launch)
Hope that helps!