if you got problems in the stack,
in time you are probably going to have more.
if you dont do it while you got the wall open, you will probably live to regret it.
if you have only a one story house it isnt all that bad to do...
but if its already doing it in the vertical stack,
it means the horizontal line is probably even much worse.
I have gotten myself out of troubles by useing a fernco clamp and plenty of silicone . Cut the clamp and use it like a band aid over the spot and smear plenty of silicone on it then clamp it down tight...