Thank you for the detailed description of the problem. We only need a few more pieces of information: Please tell us how your systems are connected to the home network (WLAN or LAN). Which Pis do you use (2B/3B/3B+/4B)? Which Max2Play version is installed on the Pis and which image (Stretch/Buster)? The latter can be found in the debug info at the bottom of the page „Settings/Reboot“. Which sound output in the advanced settings of Squeezelite have you chosen for your Pis?
Is the system stable if you only use the Max2Play players?