Need help with Lightspeed headset issue

I am looking for ideas why my Lightspeed Sierra headset squeals when I first turn it on and then gets quieter 10 minutes later. The squeal never goes away completely, but it does get lower. I know these things shouldn?t have to warm up.
Is it possible for my SL30 radio and/or other equipment in my RV9A to contribute to this problem & damage the Sierra?
My Dynon D180 does not report excessive voltage spikes. I have also adjusted squelch and sensitivity but neither resolves the issue.
When I use my passenger headset, there is no squeal, even when completely cold. I do not store the Lightspeed in the airplane so it does not suffer excessive cold or heat.
This will be the third time I will RMA it to Lightspeed and they promptly fix it each time. Fortunately, it?s under warranty so it?s just freight and inconvenience.
Ideas and suggestions are welcome. I am not an electrical engineer so I?d appreciate assistance.
Thanks.

I had a Lightspeed that did that after it travelled on a commercial flight in my hold luggage. Not sure if temperatures had anything to do with it. It worked fine as a headset without the power, but never did bother to get it repaired. I went ?Bose? and never looked back. Have to say, I didn?t notice a great deal of difference in sound quality, and Lightspeed were way ahead of Bose in terms of Bluetooth connectivity for quite some time. I wouldn?t be put off from buying either Bose or Lightspeed again. Both very good.