It's probably coded to show up in the app, and when you lock it, it becomes coded to only show as a regular amiibo.
When you try to dump/read it with another app, it just shows up as an Amiibo would, since it's just 1:1 copies loaded on there, locked sectors and all.
But when unlocked, what does it show up like I'm wondering? There must be a different mode that allows the app to see the difference and access all the banks. What kind of a chip and what size does it show up as when unlocked? I'm just trying to figure out what makes it so different from the standard Mifare Ultralight developer kits we already have, beside the button that lets you switch Amiibo.