Thank you.

I have exactly the same issue but didn't realise it only applied to the guest network. I have been trying everything to get the parental controls to work and set up the devices to login to the guest network. I have now added a device to the main network and the controls seem to be working on there.

Have been around the houses with support this week with the normal first line support questions which I satisfied. They finally said that "Since our senior engineers are on Chinese Spring Festival from Feb 14th to Feb 22nd, if these can't fix the problem of the router, we need to discuss the problem of this issue when our senior engineers are back to officeSince our senior engineers are on Chinese Spring Festival from Feb 14th to Feb 22nd, if these can't fix the problem of the router, we need to discuss the problem of this issue when our senior engineers are back to office".

I will pass this on to them. Have you had any luck with this since?

I will add my parental control devices to main SSID in main time.

Can't you block your son simply by having his devices logged into main network and then change password on guest network (or switch it off if you don't need it) as a workaround in meantime? Apologies for suggesting the obvious.