It only happens for a few seconds then it stops and only when I select the defroster after it was in another position. It sounds like the mechanism that changes the path of the air is getting stuck. I have a video but Tapatalk won't let me upload it for some reason so I will upload it when I get home.
https://youtu.be/2DcdJ2sWz60 here is the video
Sent from my PH-1 using Tapatalk