TL;DR: The bard player is arguing that lingering composition is a Performance check, and another player is stating it's Casting a Spell (Focus spell).
I have a player playing a polymath bard with lingering composition.
This player insists that when casting the composition Focus spell, on the composition’s Performance check, a critical failure is the same as a failure, and the bard doesn’t expend the Focus point (because the Focus spell requires a Performance check to determine duration, and lingering composition doesn't have a critical failure entry, only a failure entry).
My ruling as GM is that the bard is casting a Focus spell, and that the Casting a Spell rule is the active component, not the Performance check.
Lingering Composition: https://2e.aonprd.com/Spells.aspx?ID=389
Casting a Focus Spell: https://2e.aonprd.com/Rules.aspx?ID=276