I’ve hit this issue myself numerous times, and it’s a real killer. Recreating Blueprints from scratch isn’t feasible if you’ve got lots of Blueprint changes and code, and can set you back weeks.
The only thing worth offering here is some advice. Keep on top of your Version Control as much as possible, and don’t leave it took long before committing your Blueprint changes. Accept that any changes that haven’t been committed could be lost without warning.
If you do run into this scenario, revert back to a recent commit where you don’t have this problem. Copy the BP that is getting corrupted to another folder, and then check out to your latest commit again. Now overlay the backup copy you just made. You will have lost your recent and uncommitted modifications to that single BP, but if you’re keeping on top of your version control, hopefully it won’t take too long to reinstate 