Eagle F1 are OEM Tires from my Knowledge. I would take it to a alignment shop or a Suspension Shop for a opinion. In my experience and by no means am I an expert would lean towards a Ball Joint or a alignment issue. If no suspension issues then maybe a faulty tire. Do you have the issues on both tires, my bad post stated different? I assume you run the proper air pressure? Keep us posted.
It's a known issue that the factory eccentrics are prone to slipping.
This may be B.S. But is a starting point, at least worth checking out.
http://www.smokinvette.com/corvettecamberkit/