Right, and I think this played an important role in why the Supreme Court ducked API copyrightability; they’d rather not do so absent a binding lower circuit decision, or especially a conflict between circuits, preferring to let the issue percolate (and also provide Congress more time to intervene) of there is another basis dor resolving particular cases with less sweeping impact.
CAFC does not have natural jurisdiction over copyright and thus always applies circuit law.
Here, this was also a 3-judge panel of the federal circuit, and en banc review was denied.
Those decisions are already not binding on future 3-judge panels IIRC (it's been a while, honestly), and definitely not binding on the circuits