And no, all the Seanchan prophecies aren't corrupted. Many come from damane and are perfectly valid Foretelling, and it should be fairly obvious by now many of the "Omens" are dead on the money (like the one Tuon had that convinced her to meet Rand). Those omens make perfect sense in RJ's world, as they are "patterns".

Brandon has however confirmed that parts of the Seanchan KC have been corrupted.

The corrupted parts very likely date back from the Consolidation, it's almost certain very few copies of the KC as known in the Westlands have gone with Luthair. The most likely scenario is that Jalwyn Moerad/Ishamael gave Luthair a copy of the KC containing small corruptions (Hawkwing was cut from AS influence for decades, it's not even impossible his advisor manipulated him into believing the KC had been corrupted by the WT, that he had a rare untouched version that had many interesting things... like the necessity to extend his Empire to the other continents). In any case, we do know there's an "official version" of the KC prophecies the Empire imposed on everyone, outlawing local "corrupted" versions.

In Seanchan, the KC is part of a larger set of prophecies. We were apparently to learn more about it from the outriggers.