Layout Slides gets duplicated sometimes

Hello

I have created a template in PowerPoint 2007 and when producing the template
earlier versions of the template had already been starting to get used by the
users of the template.

Finally when the new template was finished and ready I now would like to
insert all slides in the new master (that the users have created using
different versions of the template). But ...

Then some of the layouts are duplicated or sometimes appears 3-4 times with
the same name of the layout but a number infront.

Anyone knows why this happens? Does PowerPoint note that the name of the
layout is the same name but looks different in some way?

Regards and nice weekend
Elisabeth