I was playing Talisman prologue while riding the bus today and something unexpected happened. I was playing the Dwarfs old enemies quest and was going for the one on the cursed glade. On the way I passed the Sentinel where I used potion of strength finishing my move on the cursed glade where the potion lost its effect. Is this supposed to happen or does this differ from the board game? I'm not sure but I've always thought the potion would still be effective as it was already drunk/used. How do you play?

"Strength and Craft derived from Objects and Magic Objects do not count on this space," Therefore it doesn't matter whether you had already drunk the Potion, as the Strength was derived from the Magic Object.

I always thought a potion already in your system were different but on the other hand if the glade can neutralise the amulet and holy grail the potion probably ain't a problem either.