Cupertino, we have a problem.
Yesterday I installed 10.8.3 after finding a disk corruption and using disk tools to repair it. It tested fine afterwards and everything seems to be working very well.
However, I also decided to turn off time machine so it wouldn't interfere with a download. I turned it off and locked it.
Today I noticed it is running again. I checked TM preferences and it is still turned off, but backing up anyway.
Try turning it on and then off again. If it continues, here are two troubleshooting article, but I'm not sure anything in them will help:
Time Machine Troubleshooting
Retrieving data ...