I have the HRM Pro Plus paired with the Epix gen 2. Four or five times in the past two weeks, the heart rate reading will spike well above 200 (which I know is not accurate). My strap is probably about 6 months old, no problems until the past couple of weeks. I do rinse it/wash it as directed, everything on it looks fine. I make sure it fits snug and in the correct position, and I even moisten it as directed (although I get plenty sweaty as soon as I go outside with this heat). This doesn't just happen at the beginning...sometimes it does, but often it will be in the middle of a run. Sometimes I can stop and try to readjust the strap to make it read more correctly, but this morning I just took it off in frustration. One day it completely screwed up my "new" max heart rate/treshold because I didn't catch it for a good ten minutes.