Thanks Barb

Yes, it is about the inverted pleat. Because the under apron is pulled further to the left the inverted pleat gets pulled open, bulging under the apron over my right knee. I'm going to try to hem the inverted pleat and press it again so that it lays flat against my leg.

Pulling up on the underapron works, but doesn't that look somewhat awkward unless one is wearing a waistcoat?