Logic Pro 9 aux channels play out of sync

I am using Logic Pro 9, version 9.1.8. While recording new tracks in an existing project, I routed three new tracks after recording to a new aux input. The aux channel plays back this new audio as if there was a full "wet" plugin inserted on the aux channel, delaying the playback of the new tracks by approximately a half second. There are no plugins on the aux channel. No new plugins were added. If I leave the new tracks set to stereo out 1-2 the tracks play back normally. This problem occurred in the middle of a session without any warning. I have checked the audio settings to ensure that my buffer is now at 1024 for mixing, recording delay is set to "o", software monitoring is disabled. I did a complete restart of the computer. I then opened another existing project and recorded a single track to check for the problem - same issue, in a different project. If I create a new aux channel and bus an audio track through the aux before sending to the stereo out, the audio plays back out of sync and delayed from the rest of the project. I tried removing all plugins from my stereo channel, not just disabling them, with no change in the problem. I also tried setting the audio unit to the built-in I/O with no change to the problem.

I am in the middle of completing a large album project and this is causing a significant headache right now. Thanks for any suggestions.