Maybe during these gaps you watch lost connection to the strap and used imprecise readings from the optcal sensor.
I would test turning off watch sensor (can just use jacket mode battery saving for in the run app settings). This way you can better see where the problem is.
the problem is that my frequency never went above 160bpm and in this race it stuck at an average of 187bpm. I disconnected the strap and it dropped to 97bpm, meaning both were broken. The strange thing is when I walked it marked right, it seems like some problem. rhythm and frequency. Does resetting the device fix it?
