Duplicate products showing in category product list

[iamTony]

LIVE SITE: http://www.novabiostorage.com/
VIRTUEMART VERSION: VirtueMart 3.0.10
JOOMLA VERSION: Joomla! 3.4.8 Stable [ Ember ]
PHP VERSION: 5.6.16
SEF: Artio Joomsef 4.6.4 with VM extension version 3.1.5

Posting here as I think I'm doing something wrong with the configuration.

https://www.novabiostorage.com/additional-options if you check here you can see the SKU: MXL100DC on the first page and the same sku on the second page. this keeps on happening to other categories as well. 

The only thing I'm changing in the config is the "Frontend default items per list view" field set to 9. I tried removing it and shows all products with no duplicates. However if pagination is on it shows duplicates.

I'm also thinking this is a sef issue. So far I haven't found solutions in the past days.

Would appreciate some help.

Thanks in advance.

[GJC Web Design]

SEF: Artio Joomsef 4.6.4 with VM extension version 3.1.5

first thing I would try is to get rid of that..  no 3rd party SEF is required for J3/VM3

IMHO they cause more problems than any perceived gain...

[iamTony]

I can't remove that as I need some controls on the urls like for example.
instead of showing. www.domain.com/main-cat/sub-cat/product it would be just www.domain.com/product

Hands are tied on that one. However I will try to switch to Joomla default handler just for curiosity sake and might lead some answers.


EDITED:
Just tried restoring to default joomla handler. still acting the same no difference. urls went to like this:

index.php?categorylayout=0&showcategory=1&showproducts=1&productsublayout=0&Itemid=255&option=com_virtuemart&limitstart=20&limit=int&view=category&virtuemart_category_id=856