Left the speaker cut off ones for me too, it looks like software glitch as output is used ny multiple source (turn lights, voice guidance etc).
Reset didn't help but waiting 20 min fixed it.

 

The cool-down fan is quite loud, but that's just how it is. It needs to cool itself down. forced induction engines generate a lot of heat. My Defender is louder than my old 2017 Disco, but that had the old supercharged V6. My Porsche and Audi both do the same thing, and they're equally loud. That's just how it is. You need a pretty powerful fan to cool down an engine bay. It's not a Dyson!

 

I had this happen last night. Only rear speakers working. Shut off the car and locked it and it was fine on the next start up.

 

^Same fix here when only the right side has sound. They somehow carried this feature over from the LR4. Part of the charm of British-engineered electronics. Funny how those of us that have owned JLR vehicles for years accept these "features" in return for amazing capability off road and in winter. People coming from Lexus are so stunned they are ready to sell when the first issue appears.

 

Had the same issue only left front speaker was working, just turned off the car waited 20 mins and was working again.