It was driving me crazy, thought I dropped a coin and it kept rolling back and forth when I made turns. I pulled the plastic panel off the drivers seat and found the culprit. A sheared off bolt with the nut still attached was rolling around in the space in the back of the seat. I have no idea how it broke off, my best guess is during assembly. Question is, do you think I should take it back to dealer (bought new in May)? It doesn't seem to affect anything....
...where it's supposed to go (couple inches above the one in view):
...what it looks like on passenger seat: