Upgraded from UE5.3 to UE5.8 and I keep getting the error in the title when saving a widget blueprint. I don’t have any variables in the graph or designer of AController type (or subclasses), so I really don’t know where to look. I presume this is some new data validation introduced between 5.4 and 5.8? I can’t find anything related to this. EDIT: Temporarily deleted all nodes and variables, and this still shows up.
The Message Log now also displays UE_LOG output. I didn’t catch that… 
That’s what I was seeing.