I also have this. I haven’t tried with cars, but the ANC seems to really amplify some deep bass sounds from the environment. To the point I hear things I wouldn’t ever notice before (e.g. different states of my air conditioner).

The problem is it comes through as an extremely loud rumble, usually in only one ear at a time.

Not a high pitched squeal, but a low pitched rumble. Goes away if I remove and reinsert, but immediately comes back in short order.

I can make it go away but only by using tips that don’t fit as well, and therefore don’t reduce noise as well (and also fall out of my ears while running).