The following member variables in blueprint.. have invalid type

Every time I open a Level containing a large BP I get the following error pop up

“The following member variables in blueprint… have invalid type. Would you like to remove them”

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 the application hangs requiring a force quit.
This is a HUGE show stopper in a current project so any troubleshooting feedback greatly appreciated!

You can try to change the LoadingPhase of some module