I wouldn’t just take things on face value. Simply check yourself for any updates. See this support link…

https://support.sonos.com/en-us/article/update-your-sonos-speakers

Hi,

Couple of days ago I connected my Sonos move 2 , with Sonos one and Sonos era 300. The last two, can connect simultaneously, but I can’t connect the move 2 to the other two speakers at the same time. 
What can I do ?

Maybe post some screenshots of what you’re seeing. That might help others here to suggest something. My initial thoughts are to perhaps ensure that you’re 2.4Ghz/5Ghz WiFi bands on your Router/WiFi AP’s are sharing network segments and are not isolated.