I only get the deceleration bump below 5 mph and only when the automatic transmission is in sport mode and 2nd gear (I downshifted let's say from 4 to 2 to slow down and then stopped without downshifting into 1st). If I just use the brakes to decelerate in normal drive mode there is no bump...
Had same issue with my iPhone, 1 time, last month, purchased it in June of this year. Seems to be ok now. May have something to do with the iPhone update I did.
My 2016 with 1000 miles had this problem on 2 of the adhesive bonds. Took it to dealer and they used 3M to reglue them. It seems to have worked, been 2 weeks since done.