I'm not seeing those exact problems, but I have seen some flakiness.
For example, I can't get anything to work with machine LatheZX. I can import the part, rotate it and set the zero location. But as soon as I try to define a workpiece things start disappearing. First the workpiece disappears and then the part itself disappears. It has actually been deleted from the design and doesn't appear in the tree.
The exact same part works perfectly in LatheXY so that's what I've been using. Milling using the Tormach machine definitions also works well, although I did have to fix the postprocessor to handle the ORIGIN cldata command correctly for 5d Hole Machining operations.
I'm currently running build 0.6 rev 33254.