My guess is that you are triggering playback 1 when it is already active. In this situation, nothing will happen.
To confirm, press and hold CLEAR, and tap playback 1's button. This will manually release the playback. Then try triggering your cue in the Master Playback that triggers playback 1. Playback 1 should then get triggered.
Based on your description, it sounds like playback 1 contains multiple auto-follow cues, with the last cue in playback 1 being a blackout. In this situation, to avoid needing to manually release playback 1, you may find it is easiest to configure the last cue in playback 1, to release playback 1.
Then, your cue in the Master Playback will trigger playback 1, and the last cue in playback 1 will automatically release itself once complete. This means you can then retrigger your cue in the Master Playback, and Playback 1 will be activated again.
As @kgallen mentions, if a cue includes no intensity information, no Up/Down times will be shown. In this situation, you may decide you do actually want to include some "dummy" intensity information. This will then provide Up/Down cue timings. The Up time can then be used to set the fade up time of the playback you are triggering from this cue.