Only exception are variables that are local to the blueprint (variables created in that blueprint).
I’m pretty sure it used to work on non-local variables in the past… such as Tick’s DeltaTime, or any function such as GetWorldDeltaSeconds or GetActorLocation, as long as it was called every frame (from Tick or some InputAxis event).
I was able to reproduce this issue on our end. I have written up a report ( UE-12022) and I have submitted it to the developers for further consideration. I will provide updates with any pertinent information as it becomes available. Thank you for your information and time.
I went ahead and double checked on this issue for you. It appears to have been resolved internally and it has been committed to github. I have a included a link to the commit if you would like to merge it into your project. I hope this helps.