beside posting stupid and non-stupid comments on this forum, I just found that I forgot to update my editor's terrain deformation due to A8.40.3 that finally auto-updates hull correctly for all the chunks, so I just modified it to show shading changes also in real time (vertex normals are not auto-updated after deformation):
simple brush based height increase, updating normals only in modified area for speed, and then updating existing entity positions manually (it means pressing a hotkey or a button):
adding some noise to a flat surface by selecting a proper brush, a proper area size, and a small enough height adjustment value, then only one click:
