I would reach out to dingwall on this.
I don’t know if there is truth to this but I have a foggy recollection of Sheldon mentioning a difference in relief from bass to treble side can be normal. I have sometimes wished for this on a few basses. lol.
that said, have you ran a straight edge from beginning to end of neck on both sides to confirm your findings, removing the action at the bridge being a factor in your measurements?
Also, the wenge necks are incredibly stable and weather has had very little effect on my wenge necked Dingwalls so at least once you get it dialled in, assuming no repairs are required, you shouldn’t have to adjust it very much over time.
The only thing I would suspect to cause an issue in a wenge neck after it left the factory would be if it got lots of hot sun through a window or hot car or something.
all that said, pics of the rest of the bass are still required