Wow ok, glad to know that... Pretty much everything I tried to throw was either damaging or destroyed/broken on fall, except "non-destructible" stuff like mundane items and equippable stuff.
Since various glass containers (like vine and other bottles) did break upon throwing, I assumed doing the same with any potion would get same results.
Anyway, even that it's not very intuitive to begin with. There should have been a "use item" interaction on NPCs and scenery.
"Throw" feels very generic and as we demonstrated, not very consistent about expected outcomes... (As sidenote : personnaly when I inspect a barely living NPC and my character describes him as "inconscious/barely breathing", I logically conclude about inability of said NPC to use an item on his own... Throwing a potion near him should not had worked tbh).