This is how Apple advised me to fix the Mach_Kernal issue, and it worked for me.
I called AppleCare about this situation. They are still logging all the situations and occurances as this is a new issue and is only happening for some and not others. The AppleCare Supervisor I spoke with said do not go back in and hide the terminal with code. What we ended up doing was re-installing Mountain Lion from the system itself. Shut down the machine>Restart your computer with Command-R depressed and then choosing the OS X reinstall. After that reinstall was done...the Mach_Kernal was gone. So then we ran the software update again to see if that same "supplemental update" was there. Ironically, the supplemental one was not but was for another. It was one that just updated Digital Photos and the Airport.
The supervisor said the "Supplemental Update" is only intended for the Macbook Air. Why or how my 21.5" desktop iMac got that update they don't know. They are actively searching how that happened. So with that step I'm fully updated and the Mach_Kernal is out of site and in the correct place.
If you have any questions...call the AppleCare people. The more calls they get the bigger issue it becomes and then they solve it. I asked the technician if anyone even reads our community boards. He said yes when they get a chance. But it's impossible to read and log everything someone posts. He said the more people who call into AppleCare..that officially opens a case # and then its sent to the technical dept.
I told him there must be something going on with the App Updates and with different devices connected to it, the iCloud, backup systems. Possibly some updates are being pushed to the wrong places computers somehow.
That's my advice to everyone. Call into AppleCare to open an official complaint...and they'll walk you through it as they did me since I'm a novice at this. it doesn't really do any good complaining about it here and the "bug reports" you can email are secondary to people calling into AppleCare filing official reports, etc. In fact I was so pleased the supervisor gave me his name and direct number in case something went wrong or that file somehow appeared again.
Good Luck!