That's a weird place for it to be sewn together...was this bespoke or store bought?
Hmmm never heard of that...first thought would be suspicious too, but if it doesn't hurt the jacket, I suppose it's okay...personally I'd leave it be.
I can't say whether or not you should cut it, but I've found the stitched lapel on a few E. Zegna jackets as well. Uncut of course.
LOL! +1 to this. It's the blind leading the blind.