To bump this topic........hoping for a Roku input
There was a recent post on the Tablo forums about a similar issue. I have tracked that down to an issue with the Roku rather than the Tablo. Sure enough I am able to duplicate that myself here. Though not sure when the issue began.
If I have a Roku Streaming Stick(+ in my case) already powered on and connected to my Network and then remove the WAN access(internet) the Roku will remain connected with an IP address. However if I power up a Roku or reboot the one that was just working it will not get an IP address from my network Router as long as the internet is disconnected/disabled.
In the case above one cannot access other network connected devices, like a Tablo DVR, to watch any content.
Edit to add....I attempted this on my Roku Ultra(Firmware 9.3.0 build 4170-46) which is connected via ethernet but doesn't duplicate. I did not try it with the wireless radios however.