We've rolled out about 20 sets of teacher iPAD mini with fixed installation of Apple TV.

We've got two teachers who every 5-6 weeks need to return their iPAD's to us to re-input the Apple TV mirroring password, some of the other installs have been working fine for over 9 months and they are being used daily and never lose the password.

Anyone got any ideas why just a couple would do this?