I am always getting notifications of either extremely low heart (47 bpm) rate or extremely high (137 bpm). Only started about several months ago. I'm sure my heart rate is none of those. Does anyone else have their Apple Watch erroneously reporting on such rates? Now, I should say, I'm assuming it's "erroneous." I have my Watchband the same tightness as I did when first wearing. Can't imagine how it could be a loose band issue.