@xbkeeper 

This is expected behaviour on all networking devices that use scheduling and session-based firewalling (link to stateful firewalling) . This effects enterprise grade firewalls as well.

what is happening is that your son is starting a game session or stream session prior to the schedule taking place, when that schedule starts then all new sessions will be blocked however the existing session is allowed to continue because the session start time is before the schedule activating.

I have some success with adding custom firewall rules to my AC2300, which may help.  Write-up here:

https://community.tp-link.com/en/home/forum/topic/171132?replyId=380000

I have no experience of the Deco but guess you'd need to do this on the main unit that's connected to the outside WAN.

@JazzPackages 
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@hansremmerswaa Can you see on the app wether he uses youtube or do you see him physical use it???(When he uses vpn)

@hansremmerswaa do you have any reccommended vpns without malware or virus?

@hansremmerswaa well i get your problem but is it really ok to be a control frea*? i mean seriously if u didn't want this this to happen you wouldn't have given him a phone i mean i got my first phone at 14-15 and tbh i wasn't that attached to it until later but yea the point is stop being a control freak and try to think for once like if u put the problem kid do your homework if not, you're not gonna get wifi.... bruh... try convince him why is it good to do the homework explain to him and try convince him that after the homework hes gonna have so much time free without you nagging him cuz of the "HOMEWORK" or assignment or whatever people this aint the 80s anymore try think

@Yuukii 

Yuukii wrote

@hansremmerswaa well i get your problem but is it really ok to be a control frea*? i mean seriously if u didn't want this this to happen you wouldn't have given him a phone i mean i got my first phone at 14-15 and tbh i wasn't that attached to it until later but yea the point is stop being a control freak and try to think for once like if u put the problem kid do your homework if not, you're not gonna get wifi.... bruh... try convince him why is it good to do the homework explain to him and try convince him that after the homework hes gonna have so much time free without you nagging him cuz of the "HOMEWORK" or assignment or whatever people this aint the 80s anymore try think

Spoken like someone without any kids, its' more than "just do your homework or you do not get any internet. I don't know where you go to school, but all the schools systems that we've lived in; the kids are expected to have a tablet or laptop to do their schoolwork. The schools will also provide them one to take home to do their work. 

You know what happens if you take away their internet/ipad - they can't do their work. Come back when you actually have kids.