I was looking at the Facebook paleography group recently and came across the following post

Now I’ve seen the reverse N before in old grave markers in country areas in Scotland.
If you look at the inscription you can see that the letters are roughly spaced out, slightly uneven and not quite the same size.
I’d guess that the inscription was written out in chalk and then carved with a chisel – hence the thickening of the curves on the C’s and D’s.
The person who did the carving may not have been the person who wrote out the original inscription – in times of shaky literacy it could be that the carver may have been illiterate, or effectively so and unsure of his letters.
Be that as it may, it doesn’t explain the reverse N – if the inscription was written out in chalk on the stone for him to follow it’s the fault of the inscription writer, or if he copied it himself from a slip of paper it’s likely he copied the mistake (or if the inscription was written cursively made an error converting from cursive to capital letters).

This is what I call the Deborah effect after a former girlfriend in my youth. The upper purple square shows a rough copy of a carved reverse N. If you look at the bottom square you will see two cursive N’s.
The upper one is the way we were taught to write in school with the curve starting half to two thirds up the vertical, and the bottom is my approximation of Deborah’s cursive capital N with the loop of the N starting from the bottom of the vertical stroke. Square it and straighten it up and you get a reverse N.
As can be seen from the Eassie Kirk session minutes from 1805 a lot of people who wrote professionally, such as the Kirk Session secretary formed their N’s correctly, in this case by an upstroke, followed by a downstroke and second upstroke.

Bit less literate people?
I don’t have any examples, but I’m guessing that people who didn’t write all the time, and when they wrote on rough paper ended up doing something like the Deborah N to avoid scratching, blotting or tearing the paper as you can see in this fragment of an 1815 list of books available to the servants at Dyffryn in Wales

who ever wrote the list almost made a reverse N by forming a loop at the bottom of the N to avoid going back over the ink and risk making a blot …