This is a very interesting thread.
I have a large reg. Sebenza that engages about 50% and doen't seem to migrate unless I end up pressing the lock bar in gripping. Like some others, though, I have found that some liner-lock knives do indeed migrate during cutting (not grip) pressure. I have some Columbia River linerlocks that do that, and I think it has to do partly with how the blade tang presses against the stop pin; that maybe the stop pin has some play or give to it during heavy cutting pressure that then creates space for the linerlock to travel further across the tang.
Jim