Galaxy S4 Freezing, Black Screen, Etc.

So, I've had the Galaxy S4 for about a year.  A little over a month ago I had to go through warranty to have my phone replaced because I was having the dreaded SIM card error.

My new Galaxy S4, which I’ve had for just over a month, has no drop damage, wear on the bevel, and no water damage, as is indicated by the three markers in the back.  About a week ago my phone updated to Lollipop 5.0.1.  As other users know, this update is visually a lot different from the previous build with all the bright colors and transition effects.  In response to this updated, I added Textra to my small collection of apps, to use in lieu of the bright orange default messaging app, and I updated majority of my apps to make sure they would be compatible with the update.

Three days ago my phone began freezing then going to a black screen.  If I had a notification, like a text, the LED light would continue to blink, as if the phone was on, but the screen would remain black and unresponsive.  The only way to get my phone to turn back on was to remove the battery and the SIM card.  In addition, it now will also freeze on both the Samsung screen and the white AT&T screen, and I will have to remove the battery ten times before it will reboot.  Sometimes it would go to black screen within 5 minutes of me restarting it, sometimes I have 6 hours before it does it.

There is no particular app that I’m using when it does this.  Sometimes I will lock the screen or the screen will timeout and when I go to use it again, it is on the unresponsive black screen.

AT&T is now sending me a new phone through warranty, apparently neither tech support person (it went unresponsive mid-call, I didn’t even get a hang up sound, just silence) I spoke to has heard of this issue.  However, still having to live my phone for several more days, I’m trying to find out what is wrong, because if it’s an app that I’m using, I need to avoid that on my replacement phone.

Last night, I did a factory reset, hoping it was a stray bit of data or error or malware or what-have-you.  I added my apps hoping it would work; it did not.  I then removed several apps (Facebook, FB Messenger, Snapchat, etc.), still to no avail.  I’m sincerely hoping it is just an issue with this one particular phone, I have scoured the web and was unable to find anything similar to my issue; so, if anyone has experienced this, knows about it, or has any suggestions, I’d like to hear them.

The non-factory apps on my phone are:

Textra, Touchpal (including English and vast night sky design), Shadow Cat LiveWallpaper, Google Voice, Rhapsody, and Uber.

Everything except Textra I’ve always had on my phone, and from everything that I've read it seems like a solid app.  No battery drain problems (even through all the restarts).

Thank you,

Kitty1606