You’re right, the DHCP lease time is 24 hours. I’ve changed this to 7 days and set the IP of one M3 to fixed. I’m going to monitor the behavior for a couple of days.
But I think you’ve directed me in the right direction, so thank you 🙂
The reason that I was looking into this, was that sometimes a speaker loses its network connection during the night and
won’t automatically reconnect to the Wi-Fi network. It had to go through a power cycle before it was available on the network again.