Just out of curiosity, where are you located? I'm wondering if this is a climate thing. For example, an area that uses a lot road salt.
If it's corrosion from moisture, where does it get in? The window?
If it's a design flaw, we all might be heading towards this.
Dealers rarely have them on the lot to make a comparison like that. Do you know another Maverick owner that could come with you to an appointment? Is there a forum member that could help you? What dealer?
I know there are programmable "new driver" things you can limit with key fobs. Some packages allow you to program maximum stereo volume, max speed and some other stuff. Could that be the cause? Try one fob then the other. I did not go with that option so I can't test it here. Plus my maverick...