the horny goat

Or is it a bug?

I've found several locations in the game where user-made potions
disappear and only 'store bought' remain.

Given that I'm a master alchemist, my potions are better than the
store bought type this is quite a blow. I found out the hard way
during one of the daedric questions - the one where you have to rescue
souls from Oblivion.

Oh hoo - getting attacked by daedroths and finding all your healing
potions gone....<heh heh>