Shadowell

I have an '05 Cayenne with a recirculation motor issue that's driving me nuts. Was working fine until I decided to change out the cabin air filter (simple enough). After that point however, when the car is started it will pull outside air when set to do so, but after anywhere from a few seconds to a minute or so the motor will start to close the recirculation flap irrelevant of the button setting. It does this far slower than if recirc is simply turned on with the button (will take maybe 20-30 seconds to close). Shut off the car and when started again it will reset to open. While it is closing on its own, if the recirc button is pressed it will close all the way, and if the button is hit right away to shut off recirc it will open part way to about where it would have been just left to close slowly on its own. No noise from the motor, disconnecting the rod from the lever the flap moves freely, no binding. One other thing that I noticed is that while it is closing itself, the level on the motor seems to be slightly jerking back and forth as it takes its time closing.

Tried searching for something similar and came up empty.

Do I have a bad motor, other problem with the HVAC? I can't see how this would have been caused by changing the cabin filter but is there a possibility of something going wrong with the filter change? At a loss.

Any and all help would be very much appreciated!