If the user calls a function (We will call it "Parent's Function") from a child blueprint and then turns around and tries to call that implementation of the Parent's Function with in the parent it's self the user will get the following error (the function is being call from a spawn actor from class node in this example)
Warning [0227.34] Compile of Parent failed. 3 Fatal Issue(s) 0 Warning(s) [in 427 ms]
Error COMPILER ERROR: failed building connection with 'Child Reference is not compatible with Self Reference.' at SpawnActor Child
Error The current value of the ' Spawn Transform ' pin is invalid: 'Spawn Transform' must have an input wired into it ("by ref" params expect a valid input to operate on).
Image is attached for reference
Head over to the existingAnswerHub thread and let us know what's up.