You’re likely experiencing wifi interference between your iPhone and the Move. I’d read through that FAQ, and apply all of the solutions that may apply. 

This issue just started happening after owning the speaker for nearly 11 months!

WiFi networks (radio signals) are susceptible to things outside of your control, they don’t exist in a ‘vacuum’, by any stretch. Just because you haven’t changed anything doesn’t mean something hasn’t changed. 

To go even a step further, your LAN can change too, even if everything is wired. Network topology is dependent on all sorts of seemingly random events, up to and including changes in the OS on your router, which more often than not is updated without intervention by you.

I believe you when you say you’ve not changed anything, but unfortunately, that doesn’t mean that nothing has changed. 

The funny thing is when I airplay to my smart tv, I don’t have any issues. 

Not sure that’s all that funny, it would leave me the assumption that the interference is more likely near the Move than it is the phone, but that’s just a guess. If you’re  interested in providing Sonos some information to look at, you could submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your Sonos system and network.

What happens if you move the Move?

The same problem occurs. I’ve even tried placing it next to the router and the problem still persists. 
 

I was on the phone with the tech for 2 hours and he still couldn’t figure it out so I left the ticket open.