What does the Piercing damage type do in Deep Rock Galactic

So with the latest Season 2 update, new weapons were added into the game. With that, a new damage type appeared unde Miner's Manual > Overview > Combat > Damage Types: the Piercing damage type.

The tooltip says that this damage type is dealt by "heavy, low-speed, sharp projectiles, such as arrows", so it's pretty safe to assume this refers to one of the new weapons, the Nishanka Boltshark X-80 crossbow for Scout.

I was curious about what this damage type exactly does, but the Damage article on the wiki isn't quite caught up yet and has no mention of it.

Only the crossbow's wiki page mentions that because of dealing Piercing damage instead of Kinetic, this weapon deals 50% less damage to Oppressors and 30% less damage to Praetorians, but that was about as much as I was able to find.

When playing the game, I've noticed that the crossbow's damage tends to vary greatly. It appears as if the crossbow is capable of damaging Praetorians even through their heavy armor, though losing a big chunk damage in the process - this is noticeable when hitting Praetorians in the head, which is not a weakpoint, but also not armored. Hitting them in the back seems to deal even more damage than in the head, which makes me believe the default bolts have some bonus weakspot damage too, even though this is not mentioned in the weapon's stats in game.

How does the Piercing damage work? Does it just ignore armor (or does the reduced chunk of damage go into the armor, capable of breaking it)? How about the unbreakable armor of Oppressors? And how about Dreadnoughts?