I had a set of damascus barrels, which had a rib relayed and were then refinished, that exhibited that tendency as soon as they were returned to me from well known gunsmith. I suspect he used corrosive flux.
After a few months of constant attention they were sent out to another smith who took them apart and found the area between the ribs beginning to corrode and had to do the job over again correctly. Glad I caught it in time. I'd have your retailer send the gun back for another if it's still new. That repair isn't cheap.
