Fixing Blueprint. A cast to reference was

I just experienced a big error that seemingly destroyed much of my project.
I rebuilt most of it but one of my blueprints is not right and I cannot work out what went wrong.

The blueprint is set up quite simply. You have an axe when you strike it on an object stuck to the wall 3 times physics is enabled.

This was triggered by an On Component Begin Overlap event I had a node coming out of the overlapping component node that went to a cast to. The reference was deleted.

I can add an additional child actor component and attach that to the other actor but it does not work well. Or it is doing something else that is less consistent.