Actually, I see that SetPipelineState() used to just be declared but now it’s implemented in the header, with a template statement in front of it. That may be causing the problem. Looks like the change was done via this PR: .com/EpicGames/UnrealEngine/pull/3512. You may want to talk to the devs involved in that. You may be able to help them if something isn’t right with their changes.