I'm not sure of all situations this occurs in, but here is the exact situation it happened to me in:
1. Spawn a ship.
2: Place wedges oriented with the diagonal plane to the right and back of the ship. Place a few of them along the X axis.
3. Place some blocks below and to the front of the wedges. These are used to see whether blocks are accurately removed or not.
4. Orientate yourself to the back of the blocks, looking at them.
5. Set the brush size to XYZ 2, 4, 2.
6. Use the brush to remove one of the wedges that is not the leftmost, by pointing the cursor at its diagonal plane. If the bug fails to occur, undo and maybe move around a bit or try placing the cursor on a slightly different place on the wedge. Make sure the brush is pointed in the forward, right and bottom directions.
I've had a few variations occur: When looking at the top-right of a wedge from the left, it would remove to the left, back and bottom. When doing the same looking from the right, it would remove to the right, back and bottom. When looking from the top-right to the bottom of a wedge, it would remove to the right, back and top. All while the brush pointed in the forward, right, and bottom directions{F21183}.
However, at all times, the