I just found this similar, and stale, issue in the Sonos forums:

This may be an Apple bug but it manifests itself in Sonos UI. So as a user, Sonos gets the bulk of the blame (right or wrong) and while this is a minor annoyance in the grand scheme of things it shows that neither Sonos nor Apple care about polish and basic details. Is anyone from Sonos monitoring this? How does Sonos work with Apple? Seems like this is something that should be escalated and just get it fixed. How hard can it be?

You have no way of knowing if Sonos has approached Apple about this or not (and they are not saying), so laying any blame anywhere is useless.  So why don’t you save the blaming and address who is responsible for fixing the problem, which we know is 100% Apple.  Sonos couldn’t fix Apple’s implementation if they wanted to, that is part of the Sonos Music Partners agreement.  

As to how Sonos works with Apple, the details are here:

https://devdocs.sonos.com/docs/smapi

I respectfully disagree. As a user of a product with an ecosystem and integration partners, I have a (reasonably in my view) expectation that the stakeholders in the ecosystem will do the “right” thing. I have a limited amount of time to spend figuring out and chasing down bugs and responsible parties. I am reporting this issue, which appears to be known and has been around for some time. I can mainly vote by which products I use and pay for. If this forum is the wrong place to raise an issue, I suppose I should call Sonos since I haven’t found an online way to directly report issues other than the community. If Sonos would like to pass the bug on to Apple that’s up to them. If issues like this fester, I can only assume that neither party cares enough to address them.

And yet the time you have spent replying to this could have been more efficiently used to post at the corporation which can actually fix things.  Why are you so eager to make post after post here, even going as far as calling Sonos on the phone, yet are so reluctant to complain at Apple?  There appears to be something more at work here than your desire to see this fixed, otherwise why not just copy and paste to an Apple forum?

you’ve educated me that this forum is the wrong place to raise a bug. so thx for that.

It’s the wrong place to raise a bug that Sonos cannot fix.  You are quite correct on that fact.  

sigh - I am compelled to reply b/c again, I disagree. not about these forums, but about Sonos’ responsibility to its users and ecosystem. The issue I reported may very well be an issue that Sonos developers cannot fix. Sonos, the company, can (and should) work with ecosystem partners including music services so when a bug in a partners product is reported to Sonos, Sonos (the company) takes the responsibility to work with their partners and provide status to users in whatever way - all to the benefit of the overall ecosystem. You clearly don’t agree and you’re entitled to your opinion. If Sonos (the company) agrees with your position regarding their responsibility to their users, I think less of them.

As I find myself sucked into this pointless discussion, I’ll bow out here. feel free to have the last word.

We know:  You’d much rather discuss corporate blame and responsibility than actually getting this bug fixed.  You’ve been very clear on that point.