Volvo truck lights issue (yeah and make don’t seem to matter)

Ok so I slipseat and occasionally have the misfortune of driving one of these cracker boxes around, various years usually 2020 or higher cuz my company keeps them fresh right? Anyway so they always seem to randomly fast blink the signals when all lights on the tractor and trailer are working properly, but a weird thing I noticed started happening.
So I deliver to big box stores, and every time I drive over that yellow shopping cart stop line, the trailer lights die. It’s the weirdest thing. I’ve tested it, I unhooked the electrical and reconnected it, reset the “check lights” indicator and drove over it again. Lights on trailer go out and the lights error indidicator comes on. This only happens with Volvos, no other model does this. Has anyone ever seen this phenomenon before?