Random Reboots Android 6.0

[forgotmyname]

Okay, I'm more than sure, I'm not the only one having this issue, I've looked up a lot for a solution, but to no avail, every solution that is 'correct', is either explained badly, or has nothing to do with my phone. I'm using a Meizu M5s, running Android 6.0 Marshmallow with a custom build, I got it merely 3 months ago, and the random reboots started a week ago. Everything was working perfectly during those 3 months, no lags, no reboots, no abnormalities at all... At first, when it happened, I thought it's just a system overload and a 'normal' crash, considering I had quite an amount of apps running at the time (just in case, the phone has 3gb ram, and 32gb internal, plus a 16gb SD card), so I just ignored it... The next day it happened when I was chatting with a friend on discord, the phone entirely froze, I couldn't do anything whatsoever.. then it came back, but I couldn't bring up the keyboard to continue the conversation, I thought its just the Google Gboard crashing. After half a min or so, the phone restarted. I ignored it again this time, but when in the evening this happened again, I uninstalled Gboard thinking it was what causes the reboots. For an hour or so, I then installed another keyboard app, then it happened again... Afterwards, I used the inconvenient system keyboard, and yeah, it happened again. At the time I wasn't thinking of performing a factory reset, because I had a lot of 'necessary' apps along with their data, but when this happened another whopping 5 times, I did the reset. For the entire day it never happened. I was so relieved at the time. The next morning I took my phone to find it turned off... I thought, 'no way its gonna happen again', and yeah it happened again that day several times, I then tried searching for solutions, but none of them worked. Some were saying to take the device back to the store and get a replacement, but I don't think I can do that lol, I've had the phone for three months already, while the ones having the issue have had the device for a few days... The phone has 1 year guarantee, though, but the thing is, I'm away now from the country where I purchased the device, and I won't be back for more than a month. I did a second factory reset, and didn't install any apps for a while, however it happened again. I also just updated my firmware just in case, but again, no help. I'm typing this from that phone, hoping it doesn't reboot while I'm doing it.

Oh, and also, the phone is *NOT* rooted.
I apologize if I provided a bit too many details, and wasted your time.