It seems that under some particular conditions the texture map 64x64 that defines the sculpted prim shape is blurred, like if it was somewhat compressed. It seems to be a problem of the viewer because if I clean the cache and restart the viewer, the object is correctly formed again. The difference between the textures is visible by eye, confronting the corrupted texture in world and the preview of the original file in the user PC before uploading. The inworld texture seems like if it was blurred. With previous viewers like the current main viewer and also the WindLight FirstLook viewer this seems to happen very frequently, while with the 1.18.6 RC2 the problem seems to happen less frequently. It seems tot happen more often when I zoom out of the sculpted object. The bug is pretty evident with one of mine objects which has a texture map with very sharp edges and has a shiny texture (it's a medieval helmet). In normal conditions the seams on the sides of the helmet are almost invisible, after the blurring some deep waves appears.