Ideally all of the wall reference lines should intersect at one point.
Then try adjusting the junction order value to manipulate which wall trims to which.
Unfortunately only two walls will trim properly and the third will just butt in.
If you still can”t get it to work or the 3 ref lines do not join at one point, then have the 2 left walls trimming as you have now.
Then adjust the length of the ref line of the third wall so it overlaps the other walls but does not touch the ref line of the other walls - otherwise they will just trim as they are now.
It may mean you have to change the position of the ref lines on the 2 left walls (to the very left side) so they are out of the way.
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11