New Mastering plugin introduces static into bounced .mps and .wavs.

Occasionally the new Mastering plug introduces static to my bounced files - they sound like a radio station you haven't quite tuned into. Today I bounced one set of measures and it worked fine. Then I bounced another set of measures from the same file with the same tracks, and I got the static. I quit, rebooted, tried again. Static. Then I turned off the Mastering plugin. No static. Then I went to the first region that had worked fine and tried that one again with Mastering turned on. Static. No idea what's triggering this. Help, help! (And thank you!)