I would have to agree with you. I have 16 S3's and 1 S4 at the moment. 4 more S4's are on the way.
I did notice something that caught my eye when you said, "no X's"
I know this is an S4 forum, but one of my S3's has a dash at the end of the zeros. what does that mean? "00000000-0000000-"
Not sure actually. X non-responsive? - dead. Just a guess. But a hard reset usually does the trick.
A simple reboot did not work.
I had to do a hard reset like you said and the dash at the end of the zero's is gone.
Thank you!
Soft resets do nothing for chips (or make it worse), have to hard reset.