Reading quickly as i have to run (sorry) ... but there is a 'feature' (which I consider a bug) in the CP walls that causes the opening reference lines to be ignored... The window/door insertion looks at the wall thickness at the window/door anchor point rather than honoring the reference lines exclusively. If you set your door's anchor point to 'head'/top then it should cut through the brick wainscot and have the casing flush with the wall above.
Cheers,
Karl
One of the forum moderators
AC 28 USA and earlier • macOS Sonoma 14.7.1, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB