What doors are you talking about ??
The Front Doors show
On interiordoors there are a group that show swingdirection and doorleave, if this is the one's you think about, they will not cut anything as they are not in a Block
If i Select and insert an opening, it opens with the 2' 6" Block, and cut out an opening when placed, save, close and reopen the drawing and the opening is still there.
V20, V21, 2015/ 16/ 17/ 18/ 19 Pro. Platinum
Deluxe 2015/ 16/ 19
Windows 10 Home Premium 64 bit, 32 GB
NVIDIA Geforce GTX 780m, 1 GB