Thanks for posting in the community, I would recommend that you try all the troubleshooting suggested in this thread, if that does not work then I would suggest you call the customer care team as they will be able to assist you further with this issue. You can find the contact information HERE.
I hope this helps, should you need anything else then please get in touch.
1. Hey guys - I haven't been on for a week and so I just had to go through three more full screens here. As we know, the QC35i firmware has been recently upgraded. We have all been 'skeptical' for about a year or so that the problem was firmware related. So from an 'evidential' point of view, as I no longer have a QC35i with an on/off problem, can someone with the problem who has upgraded their firmware tell us if the problem was happening before the upgraded and now there is a long period of time (weeks, perhaps longer) without the problem happening? If it turned out to be the firmware (which again I am skeptical over til proven otherwise), why hasn't Bose let us know somehow (versus just saying 'bug fixes')...
2. For those of you who think changing settig in Bose Connect or other 'fixes' (like reinitializing everything or keeping the wire plugged in, for example) will help - it has been shown here multiple times that it has not.
3. If you are DIYer, somewhere way back in this post are instructions and fixes on how to get it fixed.
4. If you want an exchange - even out of warrantee - there is a path to do that, but it is not going to be easy. You will be offerred an exchange for money - turn that down. You need to be PERSISTENT and keep calling and perhaps escalating until you finally can convince a Bose person that you are part of a class that has this problem. Eventually, if you keep it up, people here will tell you, you will get a free exchange.
5. I have not seen or heard anything to suggest that Bose has determined the cause of this problem. And (a) they may have and I have just not been plugged in enough to find it out and/or (b) Bose may still be looking for a pattern to determine the cause and which devices if any are included. For example, hypothetically (as I am not a Bose person), like other vendors (technology or non-technology), they could be trying to determine if it is random or constrained to certain groups say based on manufacturing dates or serial numbers. Who knows?
I opened up my headphones and bent the on/off switch pins a few weeks ago. I'm fixed for now, but not optimistic this will be long term.
My Bose qc35-1 were working fine. Following the latest software update, they have now started to turn themselves on. I do not want to self fix... can Bose fix / replace?
@CarpoI highly doubt this is related to the firmware update, likely just a coincidence of happening recently after updating the firmware -- this is my opinion after reading everything in this thread.
No, Bose does not fix/service the headphones.
If your device is under warranty they will replace it.
If your device is not under warranty they will likely offer a discount price on a new one, but many people here have reported that escalating/being persistent can get you a free replacement (you may have to call several times/days). There are many do-it-yourself fix and work around suggestions on this thread if you feel like trying (and reading thru it). Good luck.
Since this appears to be one of the longer threads for this issue, I don't want u/qiangliu's solution to get buried, so I'm going to link the thread that contains his detailed walkthrough to fix this issue with the QC35 I turning on, even when the power switch is in the off position. I just performed this fix this morning and can confirm that it solves the hardware issue.