I did a run today trying out the metronome. I used the default setting of 180 beats, 1 in 4 frequency with sound + vibrate. I stayed in sync and posted a typical run where my spm should be 180. When I checked my run in Garmin Connect it actually shows my spm as 90. In a few places where I know I got out of sync it actually shows up as 180. I appears as if the vibrate feature is interfering with the step tracking.