I stand by the point that is almost all cases it’s just extra brake pad built up on the rotors, (then again rotors don’t last forever and should be replaced once in awhile.)
I noticed my car was doing this a bit today, I apply a method told to me by a guy that sold brake pads and rotors for a living, take the car out find a nice safe stretch of road, bring it up to decent speed 55-70mph, and full brakes to the floor, repeat 3-5 times, that should be enough to take any extra stuck on pad off.
Did it twice pretty good from 55mph this morning, noticeable difference already.
IMHO, if you can find a safe stretch of road and feel comfortable doing such, try it, for me it’s worked EVERY time I had pulsing starting.
Worst off rotors are cheap and easy to replace on your own, and shops charge redicoulous prices for the service and parts.
Added benefit, Have you actually done such a thing with your car before? I know the brakes on our Rav4 are much more impressive than previously thought, when you can feel it in your chest.