This reminds me of an unedited novel posted to a forum, now removed, in which a xenocidal species which controlled most of the quadrant of the galaxy opposite our own had been known to a conspiracy within military intelligence for centuries. They were dubbed the Lefu. Their long-range scouts had destroyed some outlying colonies and exploration vessels, with very few survivors. The name and a few details eventually became common knowledge to the upper ranks of the military, but the unstoppable size of the threat was concealed. The conspiracy's purpose was to manipulate the rest of the military into avoiding a confrontation which would provoke Armageddon.
Eventually, humanity met and went to war with an all-but-xenocidal empire that was more powerful then the largest human government, but was not unbeatable. Confused generals and admirals dubbed these enemies the Lefu, and the name entered civilian usage. However, all the while, the conspiracy was watching a real Lefu sleeper fleet grow ever closer. Eventually, Humanity and their enemies had to fight for their survival against these Destroyers, who had to be given a new name, which I've forgotten.
TL;DR: It would amuse me if the Shivans were initially called Vasudans, and then the name ended up being applied to the Vasudans we know, so GTI had to come up with the name "Shivans" instead.