The only thing I could guess and it is just a guess is that when you are setting it to only use the PIR motion it is still using the camera. I have a floodlight but have not paid much attention to it because it does not see much traffic. I will do some tests and see if i can replicate your issue.
Kinda a sketchy site, but has good info. Basically, headlights (and any light) have heat so it will detect it.
You do have your sensitivity high, I would lower those a lot.
If I set it to low , when I walk out to my car it doesn’t detect me . Only when I get in and pull out the driveway do the floodlights cut on…
I’ve had countless other brands floodlight cameras and hundreds of motion sensing lights around my property for years and I’ve never had a single one get triggered on by a passing cars headlights . Not one , only since I’ve been using my wyze floodlight does that affect me …weird
The usb plug on the cam is physically different than the standard V3. There are also differences in the wifi module from what I have gathered.
The plug is removable from the cam (though pretty tough) and the one on the floodlight is shielded i believe to prevent interference from the higher voltage power right behind the cam.