My custom sovereign does not gain the benefit of faction traits.

Intuitively I thought she would.

But the slave girl does.

Why would sovereigns not get their factional bonuses, since they are of those factions?
The tooltips for both these traits (and others) say 'all units get' so either way is excusable.
But this should be consistent.
Stuff realism, if it's a problem, but let's get the gameplay right.