I'm using the XT8 in router mode and my Tablo is working great.Well, sorry to say that this new firmware doesn't play well with my Tablo DVR with the ZenWiFi in router mode. However, kept this firmware version and switched the ZenWiFi to AP mode. Using an RT-AX86U on latest RMerlin firmware as wired-only, main router, makes the Tablo happy and works fine with the ZenWifi in AP mode.
I'd love to find a replacement for the Tablo DVR that works as well. However, the only one that I've found, the HDhomerun, has other problems related to Silicon Dust's terrible HD apps, and the expensive Channels app that it needs due to the fact that the HD apps have such a bad user interface.