Mine leaked, no damage to o-ring, replaced entire cap & all is well.

 

My 09 weeped a little out of the filler cap when i first got it. Since then I replaced the o-ring, also re-routed crank case vent and put breather/filter on end of hose, and took off all the smog stuff. I think that with all the EPA crap on the bike the crankcase builds up pressure causing the oil to weep out. After making these changes to my bike I haven't seen a drop of oil leak out.