Hmm, have you tried removing the wheel to compare the left fork movement to the right fork?
I would think if something came apart or broke inside the fork, there would be a difference in how it feels.
I'm just guessing here. I haven't been into the forks yet.
AKA: Tim & 'The Adventure Cycle' VROC #24567, NEVROC, SteelCity VROC
"When life throws you curves,
Aim for the apex."