Just providing an update that further attempts to reoptimize have had some impact on the surfaces. I’ve found that after removing marks from images in MTPs that have the “outliers detected” flag, I am eventually able to get this warning to disappear - and at the same time the reprojection error goes from ~3px up to 30-40px.
Then after recalibrating and reoptimizing, some of the reprojection errors of those MTPs lower by a little, while others drop down to ~3px but revert back to “outliers detected”.
In case there is any question, I am 100% certain about the markings of the MTPs (I realize this would be a big source of error).
I have also read and am following this article, however my situation is slightly different as I am having to use MTPs instead of GCPs.