TX on two slices different frequencies simultaneously

I'm experiencing a strange problem on my Maestro.  It will transmit on both Slice A and Slice B at the same time, regardless of which Slice has TX activated.  I had a local friend verify this by listening to both frequencies on the 40M band.  It was something like 7.136 and 7.193.  He could hear me -- very weakly -- on both frequencies, though I had the rig set for 100 watts.  I could tell looking at the Po meter that it was putting out about five watts on each slice. I could not figure out how to stop this behavior.  I tried all the obvious things.  I then uninstalled the current software/firmware, and installed a previous version.  Didn't make a difference, so I reinstalled the current version, still no joy.  

I then disconnected the Maestro and powered up my computer and connected it to the rig (6500).  Problem disappeared.  Everything operated FB.  TX Slice was actually TX Slice and no TX on unwanted slice.

Reconnected Maestro.  Same problem reappeared.

I also did a direct connection to the 6500, which had been suggested to solve a previous Maestro problem, but it didn't work this time.  

What in heck could be going on here?  I'm totally stumped.

Any and all suggestions appreciated.  

73 de Carl N8VZ