I have the very same problem.
After initially creating the MAC filter, setting the blocked time in the weekly matrix, it was not accepting the device.
Restarting the router, it worked.
However, some days later (not sure if he tried to connect inbetween), no access possible anymore.
Rebooting the router every day is not an option for me…
Putting the router into Modem mode would also be bad, as it’s my WLAN access point in the 2nd floor, and I have my router in the ground floor. Otherwise I would need to add a 3rd router just beside the Sunrise router in the 2nd floor, just due to its buggy firmware.