VM2,product-attributes are shown twice in frontend

I have a problem with the product-attributes of VM 2.6.0 using joomla-version 2.5.20. I migrated the products from my old shop to VM2. When I click on the product to show the details, I get all the attributes to select color, enter name, ... twice (see print-screen 1-3), but only the lower attributes work properly. Can you please help me?

Are you sure they don't appear like that in back-end itself?

yes, I'm sure. To show you that, I've created a new product with my input in the back-end and the Output in the font-end. It seems like the attribute is called up twice and tht second time the variable with the customers Input ist overwritten.

In attribute setting there is field Layout Position, you you explicitly set it

The layout position field is empty as I think it shoud be with custom field type 'cart variant'. Otherwise what should I fill in here?

Possible values:

normal
in_desc
onbot
ontop


in_desc - is for inside tab