This seems to be a fairly accurate description of how the Gathering bug works. Credit goes to zhouzhu who posted this on the Hongfire forums.

Originally Posted by zhouzhu

After half a day into it, this seems to be the rule of bug - not even close to 100% though:
- The moment you quit and then start the game fresh will be marked as (state 1).
- After spending some time afk while leaving the browser on, it will tell you to refresh. Press refresh. This mark as (state 2).
- Somehow after you refresh, the UI will be loaded as (state 2) but the stamina value will be revert back to (state 1) after you go on gathering.

A note for resolution: If you don't want your stamina runs low after gathering there are 2 tricks:
- Keep your stamina high whenever you leave your game in (state 1). Then come back to game before the game tell you to. Which then will be count as a fresh start.
- Burn all your stamina to 0 as much as you can before go on gathering. This case will help whenever you decide not to care about what the-hell-is-states I mention earlier.

If you want to abuse it, take some time research and follow trick 1. It can yield around 2-3x your max stamina per day. But since it's a bug, I won't recommend you abuse it. Nutaku won't be happy to find out.