Do SK's still suffer from the horrid xp penalty?

[Treefall]

Ouch, I didn't realize that XP penalties were shared by the group.

I've read threads on here (from 2010) where people were complaining about seeing other classes level a few times for their one level while they were in a group. (I believe it was a Paladin talking about being grouped with a Warrior.)

If the penalties are shared, how does that happen?

So what is it? Are race/class xp penalties shared, or is the burden solely on the person playing that race/class?