Often a flat featureless surface - such as painted interior walls fail to be modeled properly in photogrammetry apps as we have all likely found at some point.
Either you get a hole and no data, a very bumpy surface when it is supposed to be smooth, or part of the wall will be rendered at the wrong x/y - like a huge bulge/distortion.
They are suggesting to accept that restriction, then manually edit the mesh in another application of your choosing. delete the incorrect geometry and replace with a simple plane where the flat surface should be.
Once done, re-import the model back into the photogrammetry application, and have it reproject the textures. your wall will then be correctly textured with the gradients of the lighting of photos taken and the final model will be as required.
Basically you need to cut out the damaged area and replace with good manually. A plane (wall) is the easiest to model as it is only a couple of polygons.
Another flat featureless surface could also be a mirror or window, these could be fixed in the same manner.
The Import model option is on the far right.