I simply wanted to store 2 references to my 2 characters in my level blueprint…
The variable type for both is set to character/reference … i had the same problem with a macro, too, but there i could replace the character-type input with a wildcard, what i can’t do now…
There looks like theres something wrong with your set nodes to me! Have you tried to recreate them from dragging them out from My Blueprint panel again?
When I make a reference to Character it doesnt have the reference selector on the setter like yours does so I think you might have broken your setter nodes somehow. If you can reproduce it consistently report it as a bug forsure 
Yes, that seems to be the Problem. A corrupted Set-Node
I had the same Problem today with 4.15. I placed the set-node and changed the variable typ from “Actor” to “PhysicsThruster Reference” (or whatever the reference for a thruster is called) and it did the same Error.
Delete Set-Node, place new… everything works fine…
