DSL Service drop during the afternoon

Here's my hardware information:

Manufacturer ARRIS
Model Number NVG599
Software Version 9.2.2h4d13
Datapump Version A2pv6F039m3.d26m
Hardware Version 0100130046

During the mid-day to late afternoon hours, my Arris DSL device loses service (there is not as much loss during the evening hours and morning hours).  It appears to happen as the outside temperature rises.  The first solution was to have engineers come on site and troubleshoot the wiring.  I have had AT&T engineers on site and service the equipment on the pole running to the home as well as the equipment on the side of my home where the AT&T services come into my home.  After that. AT&T support shipped me a new modem/router (the Arris NVG599 stats above).  I am still seeing service drop in the afternoon hours.

This is a screenshot of what the Arris NVG599 reports during an outage:

This is what it looks like once service has been restored in the afternoon:

Right after service is restored in the afternoon

Here's a screenshot from the past ten minutes, where the service has been working properly.

Morning Service

So...what should I do?  Is there something I should call and say to AT&T support?  Should I provide them the screenshots I've posted here?  AT&T has implemented two different solutions and neither one seems to be working correctly.  I'm not sure what my next steps should be.  Thank you.