Does the CM2050V have a a more stable upstream threshold than the CM1150V

48dbmv isn't that big a deal on the upstream. 

But what helps us more is a full screen snip of the whole cable connections page and the event logs. That can help us check the line. What you can do in the mean time is. 

Start with removing any amplifiers, signal attenuators, or splitters from the coax.
From there check the line for kinks, damage, moisture in the line.
Check the connectors for improperly made ends, foil touching the copper coax line, bad/old/cheap connectors, or corroded connections. Replace them if you do.
If you can, simply connect the modem right where the coax comes into the home. This prevents wiring in the home from being the issue. And some ISP’s charge if the wiring issue is in the home. So this helps prevent this.

This is the current event log and  signal page, but everything is working at the moment.  When the upstream LED goes dark (happens several times a day), I'm no longer able to log into the web interface to capture the logs.

Currently, there is only one splitter and that is at the PoE, installed by Comcast, no amplifiers or other devices between the PoE and the cable modem except the coax in the wall.  

Unfortunately, I work at home so moving the cable modem to directly connect to the splitter at PoE isn't possible and would take the rest of my network offline (e.g. firewall, router, switches, WAPs)