If you want to lock a device onto a particular IP address you can use the MAC address of the device if you know how to find it. Input the MAC address into your router or cable modem and tie it to the IP address you want and the reboot the device and it should come up with the desired IP address. I do that with all my audio devices as I don’t want them jumping around when they get rebooted.
Based on the comment here, it sounds like the speakers are working properly, just that they had the wrong IP assigned to them when you initially made you post? Was the behavior the same following a Core reboot?
If you wish to have devices on the network use the same IP address each time, then setting up a Reserved IP based on MAC address is a solution. Do let me know if that helps!