The Drukhari upgrade Ramming Blade does not apply anything to any Drukhari ships. If you select the upgrade and then play a match, you can see that it is not applied to any of your line ships. If you test with those line ships to see if they're dealing any bonus damage when you ram, you'll notice that you're not dealing any additional bonus damage. This upgrade literally has no effect at all.
This may only be possible for the AI, but if an enemy ship dies as it is casting the board action ability, the boarding charges deal 0 damage each. I'm guessing that's because the ship object isn't in the world to reference for the proper damage values anymore. Here's an example of it happening (don't mind me randomly deciding to activate my Rally for no reason when I clearly meant to click Call to Arms, even though that would have obviously done nothing now that I know about this):