Have you exchanged the speaker connections at the player’s output?

Have not changed anything.  One day all is good next time....ughhh dont know what happened.

Question…your profile shows you have a Connect:Amp not an Amp. So have you recently purchased a Sonos Amp?

If you do have a Sonos Amp are the outdoor speakers Sonos by Sonance or something else?

You should try. Connections can be interfered with by corrosion, sometimes, especially if they are ‘loose’ from the beginning. And you may not be able to feel ‘loose’, but air and corrosion can. 

That was my initial thought, connectors/connections.  Just was trying to weed other issues out before getting to involved.  I just thought it was odd because it was only the left channel speakers.  Hopefully just coincidence. 

Any ideas for better connectors than the wire ties w the lithium grease?

Unfortunately, not an area I carry knowledge in. 

If you have a multi-meter you can check the wires, both sides should show near identical Ohms readings.

With a helper watching the meter you could wiggle the various connections and see if any of them are motion sensitive from corrosion or just loose.

Swapping channels at the Amp would still be my step one.