Router Parental Controls fail to list device

[invisible_hand]

Howdy folks,

I use the 3100 Router Parental Controls by directly logging into the the router. 

I have gone through and labeled most devices through the devices menu and successfully used the parental controls for my kids' devices. However, for a child's iPad, it appears under Devices but when I go to the Parental Control menu, the iPad does not appear as an option when I try to "add a device".

Any thoughts on what is happening?

Thanks for your help.