Extra Free Stats in Party? (Unsure if a bug)

Frequency: Always
Where: Everywhere
Server: Hyperion
Character: D'momo Pascal
Job: 50 Paladin

Just unsure if this is a bug or not, but noticed that with my current setup I have 372 Vitality when I'm by myself, but the moment I enter a party my vitality goes up to 383. Is this supposed to normal?

Each class brings a buff in parties, pallys bring vit, archers dex, etc.Scholars do piety, and WHM mind I believe, the rest are straight forward.