This is related to the previous issue where if you deleted a component than there would be no errors ([Link Removed]), but instead of the component itself being deleted, the delegate has.
The error shows up properly if you use the "Bind Event to..." node from the context menu, so that is the error we should expect
Result: Open up the BP again, and notice there are no compile errors on the graph
Expected: There would be a warning saying that the delegate no longer exists
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-94890 in the post.