so, i noticed that my Ravenite Dragonborn was missing his cold resistance from the race, so i double check if it actually gets the resistance (it does) and if the issue appears on all of them, only Ravenite and Draconblood has this problem normal dragonborn has its resistance.

Quote from TheDubiela >>

so, i noticed that my Ravenite Dragonborn was missing his cold resistance from the race, so i double check if it actually gets the resistance (it does) and if the issue appears on all of them, only Ravenite and Draconblood has this problem normal dragonborn has its resistance.

 
You did not check properly then. 

Firstly Dragonborn have no subraces, they only have variants. The distinction is that a subrace features are "in addition" to the base race while variants are "instead of".

The features of the Draconblood and Ravenite variants are as replacements to the ASI and Damage Resistance traits. This is why they both have the line: "with the following traits replacing the Ability Score Increase and Damage Resistance traits."

They're not supposed to have the damage resistance. 

oh, my bad, just checked on the book, thanks anyway.