Like Macros, when logging out the pet auto hp and mp potions assigned disappear and have to be reassigned in every login . Also, when someone is leaving the cash shop his guild mates and listen buddied recieve a "x has logged in" notice every time.
I've never had that happen, I can log out and even close the client and my auto hp/mp stays the same. The only time it disappears is if your pet is put away. The 'x has logged in' notification is known.
if your pet is away and you open the equip inventory (hotkey e) the potions will disappear, if you click your pet before you click e they won't.