Parental Control of Tenda AC23 AC2100 WIFI Router

Hi there, I am using Tenda AC23 AC2100 WIFI Router with around ten devices connected to the router. I have created Parental Control to allow internal access time from 7:00am to 10:30pm for one device only. However, the router will select other devices randomly and then apply such parental control setting. It causes the connected devices cannot have internet access randomly. I have already updates the firmware to the newest but the issue cannot get resolved. Any advise ? Thanks & Regards, dummip