Rav4 2012, just at about 25K. Always brought in for maintenance, etc. Thump Noise coming from right rear while driving under 20miles or so. Going from 0 to 20 doesn't not increase the rate of the "thumps" and going over 20mph the noise is gone.
A possibility is a broken sway bar end link. Stand behind the car and look under. You should see 2 bolts sticking down, one on either side. If one is missing, that's the problem. They are in the red circles in this photo: