Like I said, there's pretty much nothing they can do to the current design to fix the problem (permanantly) other than try to get as best as they can to provide a SOLID connection between the bulb holder and the light fixture. The semi-loose connection between the holder and the fixture is what's causing the sparks to burn either the holder or the fixture circuit board or both. The reason why adding some extra solders to the bulb holder worked for all of us who had tried this kluge is because the extra solder is actually taking up the "slack", for the lack of a better word, which forces a better connection between the contacts of the holder and the fixture. The snug contacts between the bulb holder and the light fixture is key.

I would put money on that your dealer will probably going to replace your entire light fixture this one last time just to tie you over until your warranty expires since there is no "proper" fix for this design flaw.