Had to slam on my brakes today to keep from allowing another car from hitting me (he ran a light) my son and daughter were both in the jump seats in the back (we didn't get hit and everyone's fine) but as I started to drive again my son said his harness wasn't working. I pulled over into a parking lot to take a look and the bottom where you'd tighten it up was completely in pieces. The strap was still attached at the top but no longer at the bottom. He's 7 and only weighs 56lbs. Makes me now question the safety of the jump seats now. Has as anyone else had any problems with any part of the buckles?