Nokia India — nokia 3 charge draining problem due to new oreo update

Address:

Chennai, Tamil Nadu, 600095

Sir
Bought nokia 3 on july month beginning for my father. No issues in beginning stages. After oreo update. Charge draining problem arrived. With nokia support chat, uninstalled all 3rd party apps, and did factory reset in that device, but still. After charging 💯 percentage. Leaving mobile for 3 hours without usage. Charge is getting reduced to 75percent.
Please resolve this issue get me idea to go back back to old os.
Need new update in os were charge draining problem will not be there