Welcome Ashok,
That's an artifact of the momentum code, settings for the encoder in the factory firmware.
Folks have enhanced the firmware for the Nano to overcome some of the operational shortcomings for their needs.
Open source code, you can make changes.
I use Reed's firmware, have yet to try Mark's.
(Mark's with the enhancements seems to be the promoted firmware as of late)
see more info:
/g/BITX20/message/92105
