Our iPad won't sync when the screen is locked. And a sync in progress doesn't stop the "lock after X time." If it has enough songs it needs to copy, when the screen locks, the copying sometimes pauses until I unlock the screen—but not always.
Possibly related is that when I plug it in to the MacBook Pro, it often (not always) says "unlock iPad to use accessory" and won't charge until I do so. This definitely does not happen with either iPhone.
Is this normal? I don't believe our previous iPad nor either of our iPhones behaved this way. I can change the screen lock time limit, but maybe there's a better way.