It is hard to know exactly what you have unless it is viewed, so I will give a few suggestions.
Yes the watermark can sometimes be very visible on the note, even when laid flat. I find it more prevalent on new uncirculated notes.
Banknote thickness can also vary, resulting in the notes feeling and appearing different. This could be a result of the paper used, or the lacquer used to coat the ntoe.
If you think this is a counterfeit note, look at the following. On the modern Journey notes with the holographic strip, the two security devices that I have never seen 100%
- Security threat, it does not show as a solid line when held up to the light.
- Hieroglyphics number, do not line-up when help up to the light.
The bank teller showed me two notes the other day as she was not 100% they were legit, as they had a very translucent and shiny look and feel to them. After examining the notes, they were legit, and my suggestion is that someone had washed/dipped/dropped the notes into some sort of cleaner/chemical product, altering its appearance.
Your note also might be unique, as I have a few notes with very prevalent watermarks in my collection.
To answer your question, is this an error??? Once again, would have to be viewed. But I would suggest that if you cannot capture it in a photo, it might not be.
I hope this helps.
