I have faced a different issue a couple of times. The rear door starts emitting a subdued juddering noise after a few rumblers have been taken at a little higher than normal speed. After a visit to Royal Motors Service centre at Kalikapur, Kolkata, the noise was rectified by retightening/adjusting the stepney securing nuts. On gentle enquiry with the technical staff I was given to understand that the issue is due to the shorter height of the rear door (the rest of the height is taken up by the glass portion opening upwards, and not sideways). This reduced height of the steel part pf the rear door has apparently not been strengthened enough to compensate for the weight of the stepney. And according to the Kalikapur service centre, the issue has been reported by other owners also.
The rationalizing is quite normal. What is unusual is Mahindra not doing their sums right, assuming Kalikapur is right with their explanation. I hope that Mahindra have sorted out the issue on their 5-door version of the Thar due to be launched soon.