Compile 'Note' on BP Interface events. It happens in actor BPs and also BP Widgets.
A similar issue was fixed back in 4.11 with Custom Events. Could be related?
1. Open a blank project
2. Create a Blueprint Interface & open it
3. In the Details panel, add a input of any type and make it an array
4. Compile & save
5. Create an actor class BP & open it
6. Class Settings > Interfaces > Add the interface we just created
8. In the Event Graph, add an Event of the function from the BP interface
Results: The Event will have a 'Note' that says 'No value will be returned by reference'
Expected: For no 'Note' to be present and the info passed without issue
Head over to the existing AnswerHub thread and let us know what's up.