Indeed, one of these files is completely flattened,
Of course, we expect Photo Shop to be able to open its own files. What we need to do is play Sherlock Holmes and find out what is saved in that file that makes non conforming.
I have a neighbor with Photo Shop, and he sends me pictures from time to time, and once in a while we get one that wont conform.
Upon further review, we find some weird layer with an aberration of a drawing on it in gray scale gradients that just will not conform.
I recall one that he made that was a layer with some gray, line art type of design, that didn't show in the image, but he used that as a sketch for some artistic drawing.
After the drawing was made, we pulled that layer, and the PSD worked fine.
Strange things like that happen.
Fred