I have several of the C&D editions over four or five years with no problems, and none on other MM products. MM does very high volume, probably the greatest number of pipes among U.S. factories, so the opportunity for some bad materials and bad pipes is there.
I wouldn't remove the stems unless you have to. Don't make it part of your regular after-smoke cleanup. Just do the pipe cleaner and scoop and wipe out the bowl. Only remove the stem if you have to, to minimize stress on the shank.
The replacement cost on these pipes is modest, but in my experience, they last many years with no problems.