I also did find this "solution" on the Adobe web site, but to me is not a real solution.
Objects that cross the gutter on a Master Spread appear on both pages of a document spread (InDesign CS-CS2)
Issue
After you apply the objects from one page of a two-page master spread to one page of a two-page document spread, objects that cross the gutter on the master spread appear on both pages of the document spread, instead of being "cut" along the gutter.
Solutions
Do one of the following:
Solution 1: Create a new single-page master.
Create a new single-page master that contains only the objects you want on the single document page, and then apply it to the document page.
Solution 2: Manually override the master-page objects and edit the object in the spread.
To manually override a master-page object, press Ctrl+Shift (Windows) or Command+Shift (Mac OS) and select the master page objects, then remove or change the objects as desired.
For further information about overriding master objects, see Adobe InDesign User Guide.
Background information
In InDesign objects that cross the gutter of a master spread belong to both pages of that spread. When you apply a master spread to a single document page, the objects that belong to both master pages are applied to both pages in the document spread; this is as designed.