iMac Pro Audio Glitching

After listening to audio for 15-20 minutes, the audio starts glitching with crackles and 1/2 second backtracking. Could be listening to iTunes or Spotify, or watching YouTube through a browser, or playing games—it doesn't matter what, the audio will start to glitch. I can 'fix' it by switching the audio output from headphone port to built-in, or vice versa, and that will get rid of the glitches for another 15-20 minutes. Seems like a ridiculous problem to have for a pro level computer that starts at $5k. This frankly ****** me off.