>You're supposed to be able to order "a" 5532 without specifying the supplier

This is not true.

>because many vendors produce "a" 5532

This is true, in the sense of a "5532-type part". But you will note that all the 5532 variants have different manufacturer's part numbers (prefixes and suffixes) to prevent this confusion. They don't just do that for branding.

>and they're all the same.

This is emphatically and trivially not true, and it tells me you haven't done the work of carefully comparing data sheet specs across suppliers. Try it, you'll learn something.

>Different vendors' 5532s are supposed to be able to be treated as the same SKU — literally dumped into co-mingled stock in warehouses — with no ill consequence!

That might happen somewhere, but authorized distributors do not do this and volume manufacturers do not do this. You might have an internal part number with an authorized suppliers list that includes more than one variant of 5532 that has been vetted for production.

>And yes, until TI's recent move, that was true of the 5532. All the other vendors' 5532s had matching datasheet specs

Again, emphatically and trivially not true. Take a careful look at the NJM and On Semi data sheets. Spec by spec. Do the work and be amazed.

>the warehouse they're sourcing from has comingled any TI 5532s into the general 5532 stock

Authorized distributors do not do this. It gets hairy when you're sourcing NOS from grey market dealers for old designs or in severe part crunches like 2020-2022 era, but that's a different story.

>no real recourse except to change your entirely supply chain to one that specifically excludes TI

This concept is backwards. You would have an internal part number for 5532-type op amp, and it would have an authorized vendors list that would only include vetted parts. "Any 5532 but TI" is asking for trouble from someone else.

And parts do change or get updated and if you are buying from authorized distributors for production you and your supply chain and quality people will get product change notices. At that point it's your job (or the component engineer's, if you're fortunate enough to have one) to validate the new version or find a suitable alternate.