On a few occasions I've had my fuel filter come loose after running the engine for a bit. It happened once when I was on the boat for a test sail before purchasing, once again about a month later after it had run for about two hours, and now once again after I took it from the hard this past weekend. I'd checked it before leaving the yards and it was extremely tight. It seems like vibration is causing the filter to shake loose / work itself down the threads. Once it comes loose diesel starts spilling out of the top. I haven't noticed any actual damage to the fitting or the filter and neither did the yard when they were doing winter maintenance.
Has anyone else run into this problem and have any suggestions? It's very irritating to get a strong whiff of diesel and know that I'll have another mess to clean up.

Never had the problem. Try getting a new o-ring for the bowl. Your old o-ring may be crushed.