If the evidence from NASA is any actual indication of reality, then it appears that flatness is the normal shape for objects in the known universe. We have observed both the moon and Mars from right at the surface and in both cases the surface is shown to be flat. It is inconclusive as of yet, but (again, assuming NASA can be trusted) it seems that large objects tend to flatness as a general rule.
It sounds like you are referring to photos taken at the Martian surface by Viking, Spirit, and Opportunity, for example? If so this is an acknowledgement of the reality of spaceflight, which is unexpected (I guess you DID bracket that statement with a pair of 'if' statements, which I included, but still...). It also serves to illustrate what we round earth folks have been saying all along: from the ground, from the perspective of a puny human and his tiny machines, the shape of a vast, round, planet-sized object APPEARS to be flat,
even though it is NOT flat. From the great distance of earth, look at the moon with the naked eye and look at Mars with a telescope: they are both round. Look at them from ground level: they appear to be flat.
If you google "surface of Mars" you will find plenty of images that show conclusively that the surface of Mars is every bit as flat as that of Earth, and a google search for "surface of the Moon" will yield similar results. The most likely explanation is that those astronomers you mention are merely witnessing an optical illusion, possibly caused by EA, much like that viewed by NASA of Earth.
I put it to you that the 'optical illusion' you speak of has nothing to do with EA, but instead is caused by the enormous difference in scale from the tiny human/machine sized object to the vast moon/mars sized object. And having shown that the round-from-a-distance moon and Mars
appear flat-from-the-surface, perhaps one can conclude that the same flat-from-the-surface
appearance earth does not eliminate the possibility that it too is round-from-a-distance? (I won't go so far as to claim proof, merely that the possibility is not eliminated)