That log says, Panasonic TV was detected, but the AVR was not. I don't know why, because it's connected between.
What happens when using separate HDMI connectors for A/V:
- HTPC HDMI-0 --> TV
- HTPC HDMI-1 --> AVR
I guess some AVR "remember" HDMI devices sometimes, and do "default routing". So it might help to use different HDMI input/output connectors, or switch it off for a day (in case of stand-by) to delete memory. Maybe LE 12.0.1 sets a different device ID for HTPC.