HELP: 2015 Trail Electrical Gremlin

hello all.

Looking for help diagnosing an issue that's started in my 2015 Trail. Note, these issues started in the winter (think -20C). And are inconsistent, and I am not able to re-create the issue on demand.

Essentially what is happening is I will be driving along, and the head lights will flicker a bit, but if I hit the brakes, all the electrical in the vehicle just cuts out, and the entertainment system will reboot (a few seconds later). However during these "events", the vehicle continues to run fine, no RMP flutter, nothing. The second thing is if the headlights are flickering, and I pull into the driveway and shut the vehicle off, and shuts down as normal. However ALL the electronics are dead, and I cant immediately restart the vehicle, lock the doors nothing. And you can hear what sounds like a relay clicking under the hood. However after a waiting period, its like the system has rebooted itself, and the vehicle starts up just fine. I have noticed as well if there is a higher electrical load (headlights on, heater on, etc etc), these events can be triggered by adding additional load (ie. turning the brights on, or stepping on the brakes etc.).

Steps to diagnose so far:

• Red ARC trailer brake controller installed, I isolated it, and the issue persists
• AUX BEAM control pad. Isolated it, and the issue persists
• Cleaned battery terminals, and main ground to the body adjacent to the battery, issue persists.
• Measured the voltage across the battery, and it read ~13.5V. (however this was not during one of its "Events", so maybe an intermittent alternator issue?
• Looking through the repair manual, its not clear if all of these systems share a ground that could be bad
• There is a aftermarket remote starter installed from the previous owner, not sure how to isolate this but not sure how this would be related.

Let me know what you think.

Cheers.

Calvin