There's the key piece of info. So LR remembers different import presets based on file type?
Running two experiments.
First, I'm importing a folder of JPGs that I know already have 2014 copyright via the Import GUI (not synchronizing folder.) The import interface opened, and the "Apply During Import - Metadata" drop-down was set to my 2014 copyright. If LR remembers import defaults based on file type, then I would have expected to see it set to my 2013 metadata preset.
Just for science, I'm importing a folder of DNG files that are also already set to a 2104 copyright. For these files as well, LR defaults to my 2014 copyright.
Am I not running the test the way you intended? Any other ideas on why doing a folder sync would apply an old metadata preset?