OpenWrt password bug

There seems to be a bug on the 21.02 version where the password is not working when logging into LuCI after the device is on for several hours, I can log into the device (Ubiquiti AP AC PRO) via SSH but getting "wrong password" when trying to log on into LuCI. It works again once I reboot the device or turn it off and on again

Check that the rpcd process is running when this happens.