When is the last time you updated it?
I’m listening to two Sonos PLAY:5 gen 2s as I type this. They happen to be grouped with a pair of PLAY:1s right now.
I could see if it’s been a while since it was updated, the firmware on it might possibly be too old to be caught by the automated process, but it would likely need to be quite a while since it was last updated (likely years, not months).
I would recommend that you submit a system diagnostic and call Sonos Support to discuss it. Don’t post the resulting diagnostic number here, they get sensitive about GDPR.
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 Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.