I experienced this on a new pair of Meermin's. I contacted them and they replaced them after I had worn then a handful of times. I would assume it is a defect, but I don't know on what part - the welt perhaps rubbing against the sole?
Probably going to order my first shirt in the next few days. Is the consensus that one will get better results measuring an existing shirt or submitting body measurements?
I've got a well fitting bespoke shirt so I would hope for a good fit off the bat.