Building a rogue, and the description tells me Key Ability should only be Dex, unless a Racket gives another option. I chose the thief racket, which should not provide any extra options, but when I go to select my Class Boost, which is also used to define the ability used for Class DC, I have the options of Strength, Dexterity, Intelligence, Wisdom, and Charisma.
Is this a bug/missing feature in Pathbuilder, or am I misunderstanding what it’s doing?
Pathbuilder doesn’t enforce most restrictions. It doesn’t know what your GM is being flexible about, and it doesn’t want to get in the way of how people play the game at their tables.