Attempting to open a .generated.h file using intellisense results in an error due to the file not being found as the proper search file paths were not added when generating the project files.
Please read: I'm not 100% sure if this is required, as the users who reported it did not mention it, but to have this work properly in 4.19, I had to open the solutions properties > NMake > Include Search Path and click in the field once. No edit needed to be made, but after that, I was able to open the .generated.h through the steps listed above in 4.19. I tried this in 4.20 and it did not resolve the error. See the attached images for differences.
This does not occur in 4.19.2
Head over to the existingAnswerHub thread and let us know what's up.