Hi!
Have a new set of Sony wh1000 xm4.
Have worked fine for a week but two times today it suddently wont power on, i have 50% Battery, i got it back on but then i had to hold the power button for over 10-15 seconds, any idea why they acting like that? Is it some Kinda known problem with Sony?
Best Regards 
Hmm all I can really say is I haven’t had this problem. I would look at returning or exchanging them personally.
Good luck
Thanks for the advice, this have never happen before with other headphones, since they are new it’s best to just deliver them back like you say.
You could try if a newer firmware would be available and will it fix the issue.
Yes they have the latest software, what i did was to reset them, with holding power and option button at same time and after that it havent happened again, so i guess it’s “safe” to keep them? Strange issue it have never happened me before on other headphones, but like you said it could only be a bug in the software probably, because if it was something with the contact in the button it would happen more often?