Mysterious Bug ( Just loading when its not awake )

Hey , i got kinda problem with my Sony Xperia Z3 compact .
I tried many things to flash a new Software over it , but my pc wont recognize the phone .. I tried many drivers and different PC´s or USB cables to find out whats wrong ,
The crazy thing is , when my Xperia is below 1 percent and it shuts down , i can load it until it has 100 percent again ... but just in this case ! Otherwise it wont load . It will show me that i only got 1 percent but
it leasts for about 2 days .. i got no clue whats wrong with my Xperia .
It would be very nice if someone could help me :S

Mysterious vibrating once a second

I saw some very strange behavior from my Verizon Galaxy S5 (running OptimalROM) this morning. I was watching a video at my computer with the phone (screen off) sitting on my thigh, when I start hearing something about once a second -- I pause the video, and figure out it is my phone -- I pick up my phone and discover the noise is actually the phone vibrating. It is vibrating for a full second, then nothing for a second, then it vibrates again for a full second, and this kept repeating. I turned the screen on, thinking there was an incoming call or an emergency alert, or something, but there's no phone call and no notifications of any sort. After the vibrating continued for about a minute, I finally decided to reboot the phone to see if that would stop it -- which it did, and it has yet to reoccur.

I've never seen this behavior from any Android phone, so I thought I would ask the community if they've seen it and know why it was doing it.