The one I had the bowed bar on was a 2-row, so I am probably not much help. The bars are a totally different design.

Another possibility tho would be a bad spring or one broken tooth on the chord-bar holder, causing the bar to squish across the strings and hit or nearly hit where it should not. But I would expect a muddy tone more than a buzz. I hate those damn combs. They are way too soft and not at all strong enough. Sometimes the teeth break just from opening up the assembly.

Or it could be poorly cut bars, but again I would expect mud, not buzz.

Is the string definitely wound around the tuning peg and the bridgepin correctly? Is it hanging up in the slotted whatchacallit at the other end?

If it still bothers, PM me an email address and I can hook you up with a good repair dude to answer in email.

~Susan