I've used the potion to kill a rare monster and had to logout. One day later, I've came back and the potion is still in effect. Thanks for the anonymous that tried to answer, I saw that I can see the timer in the Cyclopedia > Character > Combat Status, under the "Concoctions" area.
- Do I lose time offline? No, at least not for the bestiary potion.
- Does the time count if I'm in depot or just with battle mode active? Yes, anywhere that you are online.
- Is there a difference about how the time is counted in different tibiadrome potions? I don't know.