I can’t message an interface that I’ve already implemented a message being sent to, it’s rather strange and I can’t tell if it’s intended behavior or not. See screenshot:
As can be seen, “Mana Value (Message)” is not an option even while the exact same Interface that “Gold Value (Message)” comes from. And they’re made the same way too:
Solution kinda discovered? It does bring up more questions than it answers though. It works when I deselect “Context Sensitive” in the drag off menu. Messaging appears then, I don’t know why it’s needed.
When your BP also implements the BPI, the default changes to a function from the BP instead of the BPI–a function instead of a message. Perhaps, you were calling it from within a BP, which didn’t implemented the BPI…is my guess.