GarageBand for iOS 1.2: Punch in/out unavailable during a jam session
The Record button may be unavailable during playback in a Jam Session; this will not allow you to punch in or out.
This can happen if a participant has an Audio Recorder or Guitar Amp track selected. To punch in or out during a Jam Session, select a Software Instrument track.
To record Audio Recorder or Guitar Amp tracks on more than one participant's device simultaneously, turn Band Leader Control on. Press Record on the Band Leader's device.