This use to happen to my 05.
I've since switched master cyclinders to GSXR unit and the problem is gone. I believe I tried adjusting the switch itself so that it would release properly. Loosen the mounting screws for the switch located underneath your master cylinder and push it as far from the lever contact point as you can.
If that doesn't give you enough clearance, you could slightly enlarge the holes on the switch to give you a little more room. It doesn't take much.
I'd also grease your lever's pivot.
I've since switched master cyclinders to GSXR unit and the problem is gone. I believe I tried adjusting the switch itself so that it would release properly. Loosen the mounting screws for the switch located underneath your master cylinder and push it as far from the lever contact point as you can.
If that doesn't give you enough clearance, you could slightly enlarge the holes on the switch to give you a little more room. It doesn't take much.
I'd also grease your lever's pivot.