I am using "latest experimental build" & generated a new world/save. I built the first floor of my base, then started digging a basement under the base. Once i got to stone, i dug 3 or 4 blocks lower, and am leveling the floor. I first dug the perimeter, for the basement walls, then taking out the rest of the stone, from outside to inside. Many times, there is terrain tearing, so that i can see underneath the map. There are actual blocks where the tearing is, though they seem invisible - i am unable to fall through the tearing, but move up/down as appropriate where the blocks should be.
I will grab some screenshots, & attempt to attach them to this report.
I will grab some screenshots, & attempt to attach them to this report.