Mine does as well. I attribute it to the fact that my arms aren't skinny, and I can impede blood flow by, e.g., "crooking" my elbow and compressing blood vesse

Mine does as well. I attribute it to the fact that my arms aren't skinny, and I can impede blood flow by, e.g., "crooking" my elbow and compressing blood vessels there. I also sleep on my arm, which I suspect likewise impedes blood flow to the wrist area. If I stand up, take a few deep breaths, and then rest my arm on a level surface I get high 90's right away. So i don't worry about the outliers (much).