Auto Playback is a record function enabled in Setup > User > Record Default, that automatically executes cues recorded in live on playback faders. When the cue is executed on the playback fader, any manual parameters involved in the record operation are automatically released to the cue and all other values stored in the cue are owned by that cue.
When the first cue is stored on Eos, the cue list of that cue automatically loads on the master fader. Any subsequent cue lists stored will load to the next available fader.