I added a remote tuner to the list of sources. It is about 100ms away. It works perfectly fine when tuner sharing is off. However with tuner sharing on, the DVR is getting nervous and starts complaining about a problem with the signal:
Here is a line from the log:
Statistics for ch5.1 KXAS-DT: ss=100% snq=99%-100% seq=100% bps=13413302,3265184-16334944 pps=608,243-684 neterr=96%
It might not be the only place where this problem manifests itself.
Notice: Total Cache (28.8s video + 0.0s audio)