First off I am on 2015 SP5

As you can see, all of the "ghost" ones are blocks that are no longer on the drawing, they can be deleted from here, but if you just delete it from the drawing, or explode it then it ghosts out and sometimes gives a permanent rebuild symbol.  is there a way to get these to go away when exploded or deleted?

here is one with the rebuild on exploded blocks that no longer exist.