Hello there, I have contacted CDbaby awhile back about this issue. They are not supposed to send out copyright warnings. I received an email stating their automation system has not worked and had been picking up waveforms in streamed games. They pulled what they call the sync licensing off from the waveforms of the music supposedly. If you have any problems or if they try to claim a copyright issue, dispute it and tell them you have permission to use the music as you see fit. Sorry for the inconvenience.
-Ress