Reading one of Alan Green's NV observing reports, he mentioned a Question Mark (?) feature in this nebula. Looking through my images, sure enough there it was! Just above and to the right of the bright central star in this image.
Next time I had the 16" I looked for it visually and sure enough there it was, hiding in plain sight!
I have tried for this feature in my Takahashi Epsilon (180mm) but no luck, just not enough aperture.
As with the Tulip Nebula, something else came to mind when I saw this one. Excerpts from my observing log:
"Sep 11, 2018, Z16, Home: Magnificent in the 55 afocal and 7nm filter. The nebulosity can be traced almost completely around in the brighter portions remind me of the Cylon raider from Battlestar Galactica.
Aug 29, 2019, Z16, Home: Since I had the 55 Plossl in for the last target I decided I needed another Eye Candy break and went to the Crescent nebula. The Question Mark feature was very easy to see! Attempted to pick up the Soap Bubble to the south east of the Crescent. I was on the right spot and much nebulosity faint and diffuse was visible but I could not make out the Bubble."