Some googling turned up a similar issue but no solution
It seems that some type of ‘ghost’ variable persists in the blueprint even though it is no longer visible.
If I answer ‘Ok’ to remove the variable when opening a level containing the blueprint, I am able to compile the bp and make the error go away.
However the error is still there. Every time I open the level with the BP I get the same error popup and eventually it seems to cause further problems. ie when I try to compile to remove the error rthe application hangs requiring a force quit.
This is a huge show stopper in a current project so any troubleshooting feedback greatly appreciated!