We had a few reports about this happening due to wrong Audio Hardware settings.
Please, have a look into After Effect's "Audio Hardware" preferences. The settings should look something like this, try to set it the same way if it differs (i/o buffer size, sample ate):
The problem seems to be triggered by our sound effects because they are in recorded in high quality. It is possible that some audio device driver (for example headphones) might have changed these settings.