You're going to have to remove the hands, dial and day disc and inspect the teeth in the wheels marked in the following pic.

From your description, I would suggest that possibly there has been some damage due to the quick set being used whilst the movement was in the process of a date change.
These wheels could be plastic or metal in these movements, both easily damaged when the above occurs.
If this has happened, there's plenty of spares available.

 

Thanks exactly as you said …the intermediate date wheel is a small white plastic one which on closer inspection had a few damaged teeth ..I replaced it with a spare metal version , all looks good now