I also lost one exhaust bolt on the rear (Left - under seat - exhaust hanging down about an inch on that side) bracket as well; so far the new bolt is holding.
I "twice" lost my kickstand bolt (Loctite fixed that one on the 3rd try) and I've once lost the left steering damper bolt (which I had to have the dealer order) and they replaced it on my last service.
Seems like loose bolts are a common (more so then not) problem on the F4. I have all the trust in the world in my dealer (I do believe that they check them upon service) but, as stated above I once replaced the kickstand bolt; only to have it completely fall out again. On the 3rd bolt it took the Loctite to finally put my mind at ease w/ the bolt !?! -Davis