can't buy item again if it's part of another item (healing rite) (demo mode)

[quack]

1) buy healing rite
2) buy rescue beam
3) try buying another healing rite


3) does not work

you can however buy a Healing Nova (which Healing Rite also builds into)

why can I not buy a component again? I understand not being able to buy the same item multiple times but if buying Beam and Nova is allowed, I should be allowed to re-buy a Rite too