The explanation in one of the MSQ confuses me

The one in the Lightwardens quest about the Calamities? Yeah, uh, that last one they showed looked decidedly like some kind of a Darkness Calamity which is passing strange considering that the Flood of Darkness on the Thirteenth was supposed to have made the shard useless for a Rejoining in so far as I am aware. And the same thing goes for the ongoing Flood of Light no? Unless that was simply theorizing.