Barrel deformed below the locking lugs

I was cleaning the barrel (Bar-Sto) on my wad gun last night and felt a loose spot ahead of the chamber. After getting the barrel squeaky clean you can see a slight distortion directly under a locking lug cut that encompasses maybe 15% of the barrels perimeter. It's easier to feel with a cleaning patch than to see but once you spot it, it's easily seen.  The gun still holds the X-ring with a Saeco 175 gr SWC and 4.2 of Titegroup at 25 yds so I guess it's no big deal. Just wonder if anyone has ever seen this sort of thing before. I'm the only one who shoots this gun and I've never had a squib or other incident that you would normally expect to ring or bulge a barrel. There do not appear to be any unusual wear marks or signs of distress on the exterior of the barrel. The gun cycles freely as it is a well seasoned old GI gun with Bomar rib and a Bar-Sto drop in "Match" barrel. Not exactly state of the art fits or anything.

If it ain't broke, don't fix it!

I wouldn't have mentioned it other than it seems to be a new condition and I wondered if it was an indication of an impending failure or another problem. The gun shoots fine.