What you have here is "hysteresis", i.e., the current at any voltage has 2 possible values which are "path dependent", depending on whether the voltage is increasing or decreasing. Hysteresis in voltammetry seems to be related to "charging currents", not reduction or oxidation at all. See, e.g., https://www.ossila.com/en-eu/pages/cyclic-voltammetry-troubleshooting#reproducible-hysteresis-in-baseline . As that recommends, try reducing the scan rate, increasing the concentration of the measured chemical, or use a working electrode with smaller surface area. Try googling for "voltammetry hysteresis" for more.

Enda William O'Brien ..Thank You sir. Will check