Active/online Static IP and Reserved IP devices show up as Offline in xfinity app and XB8 gateway UI

I have a number of active devices on my home network that almost always show up as Offline in both the xfinity XB8 web UI as well as the xfinity app.  I had initially set these devices up with static IPs outside the DHCP scope of the XB8 (e.g. 10.0.0.200+).  While the devices functioned fine like this, they almost always showed up in the management app/web UI as Offline so I tried switching them to use reserved IPs instead (10.0.0.195 - 10.0.0.199) but it did not help - the devices continued to nearly always show up as being offline.  They will, very occasionally, show up as Online but only for a few minutes before they go back to showing up as Offline.  These devices are active 100% of the time, so they should never be Offline.  

Is this is a known issue?