Random reboots that are "soft" reboots

For lack of a better term, I'm calling this a "soft" reboot problem. Almost everyday on my way to work, I happen to glance at my phone and it is displaying the Verizon 4G logo. Or, I'll be at my desk, look down at the phone, and the it is "soft" rebooting with the 4G logo showing. When the reboot is done, my widgets are reloading and no apps are open. BUT, if I check my "Up time" it does not indicate a reboot has occurred. For example, I've seen this happen 3 times this morning, yet my "Up time" is at 66 hours.

Stock 4.1.2, not even rooted since the upgrade.

Anyone else see this? It is very, very annoying. Sometimes it will happen as I'm sending a text, etc. Oh, and I had the same issue with 4.1.1 on a different SIII.

Did you perform a Factory Reset after the update to 4.1.2? If not, that's the first thing I'd recommend.
You mentioned something like "not even rooted since the update" - does that mean that this phone was previously rooted?
Can you think of any apps that you have in common with the other SGSIII (that was running 4.1.1) that are always running? It certainly could be some conflict between apps, or just a poorly coded app, that's causing this problem.

Sent from my rooted, debloated, deodexed Sinclair ZX-80 running CM -0.001 using Tapatalk 2

I have had problems with this. Like this morning when my alarm went off for 1 second and froze and restarted the phone. Then since the Gmail update yesterday, whenever I try to open an email from the notification list, it freezes and restarts. I am thinking about doing a full reset to factory settings but don't want to go through that work if there is another solution.