Guild Wars 2

I’ve gotten the reward for each of the tiers on different characters from the collection and bought one of each to fill in the missing recipes but can’t buy them more than once to get every recipe for every character? Buying them from the vendors says their only available for purchase once?

Why excatly do you want the recipe on each individual character? The result is account bound, if im not completely mistaken. You can craft them all on one char and then move them to others.
The purchase…I would guess, that you can reaqquire the recipe infinite times, if you are not in possession of one. Aka consume and rebuy. This is probably supposed to be some sort of failsafe in case you destroy the recipe, and giving you a second chance but not a third doesnt seem to make whole lot of sense.
Also…I wish there was only one ad Infinitum recipe. Everybody made it to unbound novadays.

Not having to level up professions again and tiny bit more convenient with everything on one character. Tried logging into a character with a missing recipe, it wasn’t available for purchase

just unlock the recipe on the character that has crafting discipline unlocked. in case you accidentally used it on a character with no crafting profession, submit a ticket to support and im sure they can help you out.