Tried destroying a small Cryson ship with a high damage singularity weapon (Cryson bombard or equivalent). The weapon demolished shields and armor very quickly, but the enemy ship, now with 0% shields and 0% ignored damage from that weapon after that. I had to cherry tap it with another low damage weapon to kill the ship.

Later, I repeated this against a large Cryson ship. Once again, armor was wrecked, but hull stayed at 100% until I switched to a weaker weapon.

I checked the Cryson file to see if they had any special defenses, but they did not appear to have any.

I do not know if this is limited to Crysons or if it is a general (rollover) problem with attacks that cause very high damage against very tough opponents.