I believe they've added a waiver with the line that reads something like "You must spend 1/2 your build points as long as you can afford to build a ship. If you don't have enough BP to build a ship, you are allowed to bank the entire total."
Since the Mirak can't build BCHs yet (not designed), and the Mirak can't afford a DN, they're able to bank both build points for next cycle, but they'll have to build a ship next cycle as they'll be able to build a DN then...