Or being the first to refer to the corpse as Jah (god)...
That could make sense... The only way I could think of to get completely stricken from the history would be for the emperor himself to say that it should happen, as they still have the traitor legions listed... And with the emperor being like he was, if one of the legions started referring to him as god and refused to change, he may very well have disowned them, and in that case, it's also probably not likely that they would have become traitors either...