Earlier today, when trying to power on my Nexus 6, I had a strange thing happen. I normally power on my phone when it is still plugged in to the charger, and I tried doing that today, but after holding in the button for several seconds, the phone did not start to power on as it normally does. I tried unplugging the phone from the charger and powering it on again, but still nothing. When I plugged the phone back in to the charger, the phone began to power on immediately, but not before the hidden notification light turned green for a second. After the phone finished booting up, I got a low battery warning, as my battery was 8%, even though it was at 75% last night when I plugged it in.
Does anybody have any idea what could have caused this? To make sure that everything was working properly, I turned the phone off and on again without it being plugged in to the charger, and everything seems to be working fine, but I am curious about what happened. I am running the latest version of Android Marshmallow available for the Nexus 6 (build number MMB29Q), and the device is not rooted.