Jan 12, 2020
That was exactly my experience. It started about 4 months ago and then stopped for a short period but came back with a vengeance. Unless your headphones are less than a year old Bose do not provide support for the issue.
Ive purchased another set of headphones from a different brand. My research into this problem uncovered a lot of defects that pop up 2 - 3 years after purchase, so I didnt want to stay with the brand.
Aug 17, 2020
I am also experiencing random "bluetooth device list cleared" right as i get into a podcast or music my QC 35s.
Aside from the reset instructions and call the regional office, has this issue been resolved?
Hope they are not obsolete. I expected more out of the gold standard headset!
Nov 8, 2020
This issue has yet to be fixed and has affected any brand loyalty I might have for Bose. I cannot recommend this product to any new buyers that might think Bose offers quality products.
Resetting the device and updating the firmware has not resolved the issue. Completely frustrates any convenience or utility of the product.
Feb 19, 2021
So I'm not a Bose employee but I had the same problem and as of yesterday I've conclusively figured out why this is happening and a fix. This is not a software issue. The on/off switch on the headphones is failing. The model of this switch is JS207011SCQNR and can be found very cheaply at https://www.digikey.com/en/products/detail/JS207011SCQNR/CKN12245-1-ND/6071287 . If you are hearing the "ready to pair" followed by the bluetooth list cleared message, then this is for sure the issue. The switch has 2 modes on/off and pair. Pair is when the switch is all the way forward. The switch breaks by triggering pair when its just in on mode and this is why you are getting the reset.
Fixing this does require removing the old switch and soldering the new one. You can get access to the switch by unscrewing 3 screws. This video gives you an idea how to get access (note: this video should just be used to get an idea how to get access. In the video they are fixing a different problem.) https://www.youtube.com/watch?v=DGepP74hEcc
Also note that if you don't disconnect the battery while putting in the new switch, it's possible you'll trigger a sort of battery short protection mode or just completely drain the battery while you are putting the switch in. If you did so, then the device will require being plugged in before it will start again. Also when soldering the switch back in, make sure to keep the switch within the white square indicated on the circuit board. Otherwise, when you replace the headphone back, things might align funny or too tight.