When you edit with OOTB tools are you just changing an attribute or moving it around / snapping it to a wire, etc.?
Since the error doesn't give the class name and just the object ID have you verified that Object ID is the same as the elbow your tool is trying to edit? Or is it the OID of the wire it's connected to? It could be the shape of the wire it's snapped to that ESRI is complaining about. You may also want to check the wire near that elbow to see if there's any overlapping wire features or strange vertex placed in strange places.
This could be a geometric network related issue where it's not snapped correctly, etc.
Or it could be something to do with the actual elbow feature itself.
Have you tried using the geometry repair tool?