I would think this should only happen at stereo settings of >100%. Have you tried reducing the stereo field to 100% or less to see if the phase issue still exists?
Happens even with a 100% stereo setting. But I'm wondering if there's some kind of bug with the beta.
While I was playing later with the double tracker, I got a really exaggerated phasing sound while using the double tracker. It was just sweeping up and down every time I played. Haven't restarted the Kemper, but hopefully that will remove the issue.