There is nothing wrong with any of these worlds. And that... is not right.
No scan of these ten planets ever returns an anomaly. Composition, weathering, orbital history, all of it agrees, world to world, past any tolerance a survey instrument is supposed to allow for. Nothing here is broken. Nothing here is even unusual, taken one at a time. It is only in comparing them that anything feels wrong at all, and even then, no one has been able to say exactly what the wrongness is. Only that it is there, and that a second look does not make it go away.
Whatever accounts for this was not put there to be found. There is no seam, no signature, no error, save one: a single world that will not agree with the rest, no matter how many times it is measured. It offers no explanation for its difference. It simply declines to match, the way the others, for reasons no record has ever given, agreed to.
Older logs describe the sensation as reassuring at first. The later ones stop using that word.