I'm seeing the same thing here. I just got my HDHR Prime last night installed TVHeadend. My muxes get sorted out just fine, but when I click the "Map DVB services to channels..." button, nothing happens. In the log, I get web interface: Service probe started on "HDHomeRun Tuner x", but that's it. In fact I came here to try and fine out what's on.
Using version HTS Tvheadend 3.2.34~gfaee94b~precise.