Error with intersecting plane... happens too often.

I’ve had this happen a few times over the last few days, but I end up getting planes being calculated way out from everything else.  I’ve tried control pointing in other situations and found it didn’t help.  What’s the best way of keeping this rubbish out of my final scan?

It happened earlier where I had 4 paintings next to each other, constructing them alone left them with little depth data to go by, so when I aligned all 4 they looked great, except the 4th on was skewed about 35º of axis.

Other errors I’ve had that are similar, is a sort of ghosting where it’s reconstructed everything twice - just misaligned by some small factor.

I haven’t undistorted the images at all, they’re all well exposed, low ISO, sharp as tacks.

Love to know if anyone can understand my issue here! - thanks, Dan.