Parental controls does not show usage

I have an RBR50 and a satellite.  I'm trying to limit the amount of time my kids spend on youtube.

Here's what's odd.  I don't see any usage on the devices assigned to the profile.  I reboot my router, and time is then logged.  But...only for a day.  The next day, nothing- it's as if the devices aren't being used at ALL.

I see the devices online and assigned to the profile.  But useage is zero.  I'm not sure why it works one day but not the next...