1320 sometimes unlock screen, sending to warranty ?

[Pouknouki]

Hi everyone
So I've had my 1320 for a long time (almost two years now) and I have a question. Since the beginning, I always had a problem with the lock screen: sometimes, pressing the unlock button won't unlock it. I then have to press the power button for 10 seconds and restart it, and I have to set time back to what it should be (it's reset to the date of the build). Yesterday, I decided to install Windows 10, and the problem is way worse than before. It's almost every time I lock the screen that it won't get out of sleep.
So here is my question : it's still in warranty. If I send it, will they be able to fix it? The problem is very difficult to fix because I don't know how to reproduce, the crash will occur randomly but way too often for a normal use. What should I tell them in the letter ?
I of course plan to downgrade back to 8.1 before sending the phone, because anyway it is unusable in the current state.
Thank you in advance

PS : I already did multiple hard resets

edit : sorry for this useless title...

 

[Captains]

Does a double tap not wake up your phone? Sometimes I wave my hand over the sensor first. I did have a problem with the power button in the beginning. I noticed that a very small plastic piece had disconnected from the actual switch. (remove the cover to see) With some small tweezers I relocated this and all has been fine. I would suggest that this is a fault in design as its a little to delicate.
As far as date & time I have mine set to Auto detect. I hope this is helpful.

 

[Pouknouki]

No it doesn't unfortunately and it's not a hardware problem, it's software. Or at least something in the hardware (maybe ROM or RAM) that makes Windows Phone crash and prevent it from recovering normally. The power button works perfectly well.