This is a known minor annoyance with the Deco system.  It’s supposed to avoid conflict with other devices by picking an unused address range when you install it, using 192.168.0.x as it’s first choice.  However it sometimes gets confused after a restart or update and thinks there’s a conflict when there isn’t.  In my opinion, once I’ve got a router set up the last thing I want changing is it’s address - everything else should keep out of it’s way.  It’s also a nuisance for statically configured devices as they can’t follow the change and l lose network connection.   See this thread for an example: https://community.tp-link.com/en/home/forum/topic/156593

You can change it back in the “LAN IP” section of advanced settings.  Check that the addresses in DCHCP server have changed back too.

Thanks for the feedback. I suspected, but it's good to know the cause. It's not much of an issue now that I know, but will have to remember if it happens again next year. I'm going to look into alternative options for shares so the server can broadcast. I don't know if that is possible, but my Plex server continued working and a friend who is a network expert explained this is due to how that application broadcasts rather than shares passively.

Take care