Problems with SEO-URL to product page (categories have disappeared)

[Tiger78]

After I did an update from VM 2.0.20b to 2.0.26d, I have the following problem with the urls to the product page:
Before the update:  www.example.com/category/sub-category/ebook-detail.html
After the update:   www.example.com/shop/ebook-details.html?site=1234&type=text&....

I use the URLs in the product information.

First problem: If I enter no URL in the product information, everything works fine, otherwise the categories disappear.
Second problem:  Furthermore the URL-parameters of the product information url will be appended to the URL to the product page.

If I assign the product of at least two categories, the url to the product is correct, but the canonical is still not correct. The parameter are once again added to the canonical url:
<link href="http://www.example.com/category/sub-category/ebook-detail.html?site=1234&type=text&...." rel="canonical" />

What could be the cause?

[jjk]

Check if you have enabled 'Adds Suffix to URL' in your Joomla Global configuration > SEO settings. This should be set to 'No'. when using Virtuemart. Otherwise the system produces duplicate suffixes like -detail.html and the SEF urls won't work. The VirtueMart default SEO suffix is '-details'. You may change that to '-html' or whatever you like, but don't leave that field empty.

[Tiger78]

The SEO suffix in VM is '-detail'.
Now I have disabled 'Add Suffix to URL' (file extension) in Joomla SEO settings.
So all URLs are without '.html', but the problem is exactly the same.

EDIT (now I have found out): If I disable SEO in Joomla, then the URL to the product page is: www.example.com/index.php?option=com_virtuemart&view=productdetails&virtuemart_product_id=2093&virtuemart_category_id=http://partners.webmasterplan.com/click.asp?.......

The virtuemart_category_id is wrong! It´s the product_url instead of category id. But I can not find the file where the error must be???

By the way:
The folder /components/com_virtuemart/views/categories does not seem to exist in the actual Version 2.0.26d. Can I delete this folder?