Somebody commented on the Patently-O blog the other day that a claim that is patent eligible under §101 can become patent ineligible simply by narrowing the claim to recite a specific function that is a purported abstract idea. Judge Linn made a similar comment back in 2016 in the oral argument of IPLearn-Focus v. Microsoft. You can listen to that sound bite here:
You can view the previous post about the IPLearn-Focus v. Microsoft case [here].