So it sounds like you could have a corrupt asset or you have changed an .ini config file, if the same set up that is broken in your own project works in a clean one.
You can try going into your Unreal Projects folder and deleting the config folder of the project you are having issues with, to see if the issue could be related to a setting you might have changed, but not realized.
Before you delete any files, be sure to make a copy of the original first in case it causes an unpredictable issue. Let me know once you have tried this and are still experiencing an issue.
Cheers,