This happened last week, one of the rear doors was rattling really bad. Once I got to inspect it closer the bolt to the lock was gone not broken. I checked the other bolt on the other side and it was loose and about to come out. I checked the front lock bolts and they were fine. I removed the one bolt and took it to find a replacement. Thanks to Ace Hardware found a replacement bolt. Check your lock bolts. If you need a picture I had take one if needed. It was an easy fix.
Thanks for the heads up, you are not the first I have heard having the bolts come loose. Maybe some lock tight is in order.
It is the bolt on the right. 10mm socket - 6Mx18 (6mm) bolt. It is easier to get to if you take the cover off, which are the three black bolts. Easy easy fix, if I can do anybody else can. Point of this post, if you have door that does not shut right or is super super loose check this little bolt. And yes, locktight added. 
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Mine did the exact same thing... Thanks for posting the bolt size. That saved me an extra trip to town.
Got the 10mm bolt, which was way too big! Fortunately I grabbed some 8mm and 6mm bolts. It turned out it is a 6Mx18 (6mm), not a 10M (10mm). The bolt head is a 10mm, but bolt sizes are specified by the diameter of the threads, not the bolt head.
