Due to the aura lingering for 3 seconds, Bottles keep on refilling even when already outside of its range, until the buff is gone.
That but with an exception when you used Teleportation (not mentioned in the wiki).
Just tried in DOTA 1 and it does not refill under the fountain heal status that still linger on the hero when I use bottle. Trying to contribute here :).
Sorry my bad about that Teleportation stuff (I was so wrong.). It does work when you teleport and you can use bottle charge as long as the aura lingers without reducing the bottle charge. *Raised from the dead topic