Stupid Apple Time Capsule keeps disappearing.
Turns out the IP being advertised over Bonjour is wrong and I have not figured out how to fix it.
I used a Linux system with avahi-tools installed
]# avahi-browse -a -r -t
= wlan0 IPv4 User's Time Capsule Apple File Sharing local
hostname = [Users-Time-Capsule.local]
address = [169.254.65.2]
port = [548]
txt = []
= wlan0 IPv4 User's Time Capsule Microsoft Windows Network local
hostname = [Users-Time-Capsule.local]
address = [169.254.65.2]
port = [445]
txt = ["netbios=H=n"]
= wlan0 IPv4 User's Time Capsule Apple TimeMachine local
hostname = [Users-Time-Capsule.local]
address = [169.254.65.2]
port = [9]
Well that's not right when the subnet is a 192.168.10.X
Checking the DHCP client table of the cable modem shows the capsule was given a valid address and I can even ping it. Still, the wrong address. The AirPort Utility can't greys it out since it can find it. Oh and it's connected to the router via Ethernet to rule out wifi issues.