Okay let’s take cat folk for example they have an alternate racial trait called cats claws which give a 1d4 claw attack. Then take a look at abyssal bloodline bloodrager and I just realized how awkward that is to say. Anyways the bloodrager gives a a claw attack that deals 1d6 for medium creatures from the get go. So that begs the question which source of claws wins? Granted these are just examples that I noticed first there’s probably other ones out there that I’m not aware of.
The abyssal bloodline claws are not "always on", so if you are not actively using your bloodline claws, there is no issue: you use your racial set.
When you are using the bloodline claws; they override the racial ones, effectively increasing your claw damage from d4 to d6.
This is different when you have more than 2 pair of arms, one of which has natural claws. In that case; the class claws apply to non-clawed arms, indeed granting more attacks