I ran into same problem today using 4.9.2-2707645.
After adding a binding and 1) deleting binding function from graph editor functions list or 2) Deleting End Node in node editor, error message is displayed:
“Binding: Widget ColorAndOpacityDelegate(or other property name) property. TextBlock 5: Binding: ‘None’ : Couldn’t find None in HUD” (I translated it from Japanese, so it’s not verbatim)
To fix it you have to Remove binding by clicking on the “f None” binding button for property you’d previously binded, and then choose “Remove binding”. 'll fix compile error, but note that doing will NOT delete binding function from function list in graph editor.
error message doesn’t make it easy to figure out. (Would be nice if it just had a note saying "Try removing bind from Textblock_X’s X property.)