Bard Left Trigger in Perform Mode Does Nothing

Possibly I'm being dumb and not understanding something, but according to the controller layout given by the devs here the left trigger is supposed to activate the 2nd Quickslot.

For me, the first Quickslot works fine but the 2nd does nothing (I've tried several songs, making sure none of them were the 'in combat' ones).

I've noticed that when mapping them to their slots, trigger 1 actually says quickslot 1 but the rest just say "pinned" - there's nothing saying "quickslot 2 / left trigger", so I was working on the assumption that the left trigger was the first pinned option (the other possibility being that something is wrong).

Am I missing something or is it not WAI?