Either you have a bad fork seal and oil is leaking out of your fork down the leg and onto the rotor, or you have a bad caliper seal and brake fluid is pushing out of the caliper behind the brake pad and onto the rotor.
Either way your pads are now junk. Once they are contaminated by hydraulic fluid they will always be compromised.
Take this opportunity to switch to better pads like EBC HH+. Once you have the oil leak stop you will be glad you upgraded the pads.
2002 R6 49k miles