- Could you show us a screenshot of your workflow?
- When removing from parent, are you plugging in the widget reference in the object reference input of “remove from parent”? I think, remove all widgets is a bad idea and I think that is what is causing that error.
I have a faint recollection of having a similar problem when I started out with UE and at the time I did not understand references so I got a lot of "none trying to read"s and stuff like that popping up. Not sure if that is what is happening for you though.