This complete blower/coil unit was pulled from a 2004 to add to my spare parts pile. I happened to notice that the foam for the ceiling/floor damper, had come loose from half of the door, not to mention that it was put on crooked.
Although the fan at higher speeds may simply overcome the foam and push it open, as it's pointing in the direction of the airflow, this may also cause damper motor jamming, or failure. Or possibly loss of airflow.
I left the pics at fullest resolution possible so it's easier to see what's going on.













Bottom drain pan removed, the foam has released and unfolded to the left.