When I use heightmaps that i bake externaly as a base i get these stepping artifacts even though my bakes look smooth. any ideas where this might come from. Tried 8 bit and 16 bit images, png tga and tiff. Same issue with textures from xnormal, maya and marmoset
Your screenshot shows the hallmarks of an 8 bit heightmap which only has 256 discrete levels between black an white i.e. lowest possible and highest possible. The number of levels is restricted even further if your heightmap is mainly mid values.
This is confirmed in your 2D view which shows the height channel as 8bpc.
Use 16 bit throughout the chain for height information.