In practice, nobody uses IPv6 for printers, so it'll work just fine over IPv4.

I used a printer as an example of a local device, it can be any other device: a smart lightbulb, a TV you're casting to, a SIP phone, etc. And I used Android as an example of a device where you can't easily change the source address selection preference.

What is more shocking is that this problem has been known for three decades, yet somehow nobody cared enough to fix it. And it's far from the only issue.