I recently decided to make some new characters on my accounts, and each one claimed a Desert Kangin Saddle, only if the Account had TDS did it get the HP/Mana buff any account without TDS gets only the mount, also tried a Verdant Hedgerow Leaf and no HP/Mana. It seems to be some kind of bug related to owning TDS.
You'll perhaps be pleased to know that today's patch ought to have fixed that issue, according to patch notes.