2014 Cascadia-flash of light coming from under cab

Can anyone tell me if there's a known cause for a flash of light that happens intermittently? It's clearly visible as I'm driving at night, mostly from my driver's side window, making me think it may be a bad ground, perhaps? It started out happening maybe once a week, and for some reason, the radio would always turn off and on again when it happened, but nothing else seemed to be affected. Now it happens at least once a night, and the radio only seems to be affected maybe 1 out of 5 times. Some of the other drivers I work with have noticed the same thing, and I'm sure I've seen it posted on the internet before, but can't find anything now. I contacted Freightliner directly a while back (that conversation is also lost now, but I think I may have done it as a comment on their Facebook page, I'll have to check again), and they were surprised to hear of it. They said they'd look into it, but I haven't heard anything since.

 

I'll check under there tonight, I kinda suspect it's a grounding issue. Nothing has been affected except the radio, as weird as that sounds, and even now that's intermittent.

 

Nope. I even contacted Freightliner with the issue at the time. I may go ahead and try to contact them again today.

 

It's coming from under the cab, definitely. I've had one of our other drivers verify it, at least from a distance, on nights when we're able to travel together to the Portland area.