mbdev5: Element > Block appears as duplicate

Hi

I have created a header-block, which is set to be displayed on product-kategory-pages, but it's displayed twice pon each cat-pages, as you can see on this screenshot.

Can you please help troubleshooting this?

Here you can see the location-settings:
http://media.macbay.net/_support/gpp-elements-block-issue_2865A318.png

Whenever I remove the "Product Category Archive" location, the header set for the "Entire Site" will be displayed (it's a completely differtent one), but after adding it again to the locations of the Element, this header appears twice.

Admin-Login in private notes.

Thank you in advance and kind regards,
Sascha