Rage resets to full on changing zones - intended?

Playing Swarmblade and noticed that my rage resets to full everytime I change zones.
Is this intended or a bug?
I don’t have a problem with it, in fact i like it, just curious if this is the way it’s supposed to work. Mana doesn’t reset if you’ve depleted all of it before changing a zone, instead it keeps recharging slowly during any zone swap.
I expected rage to always decay until its gone unless you have the “No rage decay out of combat” Passive which I have, so maybe thats the cause of it?