What fix is needed? I get the useless slightly better potions all the time. Seems to be working as intended (even if it's not good).

IMO the perk should be changed to give a low chance of dropping tripots instead, at least that'd be useful.

Yeah, it's weird that it's not addressed. Maybe there's some issue with adding new potions to the game, since I can't imagine it's as simple as the potions internally missing their extra effects. If the dropped potions can't actually be fixed, maybe his passive should just drop the Alliance potions instead.

Surprised we didn't see him get a second 125 rapport quest, too, since Bastian current has fewer quests that raise his rapport by 125 points than other companions.

Bastian is unique in that he is the only companion who comments when bartering with merchants. He says the following lines:

“Magic is like strong wine. If you're not used to it, it can make you drunk."
"Some say gold can't buy happiness. It seems to me they just don't know where to shop!"
"Unfamiliar magic is like drinking strange wine. Eventually there will be a price to pay."

I would have Bastain gain 125 rapport from completing an Alchemy daily crafting writ. His commentary above would be removed from bartering and would instead be said when turning in the writ. The lines don't entirely make sense for turning in an Alchemy writ, but they don't really make sense for bartering, either, and this would let Bastian have an additional 125 rapport quest without having to bring his actor back to record new lines. Plus, it'd tie his passive in with his rapport changes better.