applying a gradient to terrain curves in QGIS: problem

Question

I'm trying to apply a gradient to terrain curves generated from a geotiff. I then choose a graduated style with a gradient color palette.

everything seemed fine until I noticed that from a certain altitude, color is wrong. look at the top of peaks, suddenly light-blue (= low altitude) instead of dark blue (= high altitude)

geotiff looks fine:

Anybody knows the problem or has a solution?

Answer 1

These are contours you are talking about in the upper picture.The density of those make it appear lighter or darker.The DEM is what you should care and as you said it looks alright.