This doesnt work. Im having the same issue but I tried your solution. The new duplicated blueprint simply gives the same error. It cannot compile because the variable is invalid, but the variable doesnt exist so I cannot delete it or fix it.
I an really hoping there is a fix, because I literall have about 50+ hours worth of blueprints in my project that are now trashed all because I changed a structure. Literally every blueprint that referenced that structure is trashed.