Thanks for reaching out.
I can't currently see any 18 year old on your account but have checked the settings and this should be allowed for that age group during Play.
I can see there was a person on the Young Adult (18-20). I can see they tried Facebook just after 9pm but they were in Sleep mode and so they were blocked. They were subsequently moved to the Adult (21+) age profile. Can you try move them back to the Young Adult (18-20) age profile and try this again, making sure they are in Play mode please? If the issue persists, please reply here or open a ticket with our Customer Support Team using the link below.