The issue can manifest in two ways:
- If you stop playback in the middle of a sustained note or chord on some audio instrument tracks, the remaining unplayed portion of the note or chord will sound the next time the song is played.
- With affected DSP plug-ins, the issue is slightly different. If playback is stopped before reverb or delay tails of any of the plug-ins decay fully, the remaining tails will sound just before the first region in the track is encountered on the next playback.
If a bounce is performed in situations where the next playback would exhibit this issue, the resulting bounced file will also exhibit the unwanted audio snippets.
This issue occurs with certain Audio Unit instruments and DSP effects plug-ins. At the start of playback, Logic sends a standard reset message that tells all plug-ins to clear their audio buffers. Some plug-ins do not respond properly to the reset message.
Those plug-ins that exhibit this issue need to be updated to respond properly to the AudioUnitReset() call. None of Logic's built-in plug-ins are affected by this issue.