To fix this, when you update your status you will need to, before you post it, remove the location. Hover over the location below the status you have just written and click on the X to the right of it to remove it. Post your update. Done.
In the future, it shouldn't automatically add the location again. However, if you had to delete your cookies, or if you are on a different computer, it may try to add the location again.
Note, you can also use this feature to change your location, including to somewhere you are not.