Magento - Broken Catalog - Need to troubleshoot and fix.

Magento - Broken Catalog - Need to troubleshoot and fix.


Job Description


We are a web development company that specializes in front-end design and development. We have a client that has a Magento store with approx 9,000 products. We have a number of extensions, including the following extensions from magento connect :
Ahead Works - Blog
Aschroder - SMTP Pro
Brim - Page Cache
Business Decision - Interakting Slider
Fooman - Speedster
Magentix - Social Bookmarking
Order Comments (Not sure.)
Organic Internet - Simple Configurable Products
Phoenix - Money Bookers
Redstage - Abandoned Cart Email
TBT - Better Store Search
TM - FireCheckout
Webshopapps - Handling Matrix
Webshopapps - Product Matrix
Webshopapps - Tiered Produts
White PIxels - Order Comments

And the following we have manually developed for this site:
"Apply Coupon" (Allows for coupons to be applied via external link)
Laprobeta - Cupon (Allows for coupons to be applied via external link)
Category Product Export
Coupon Usage Export
Order Export
Product Status Update
Bulk Product Importer

The issue is fairly simple. When viewing a category of products, when you click next (to go to page 2), it shows you some products from page one. The same issue occurs with search. Because of this, we can not be sure that the customers are seeing 100% of our products- and this is certainly causing a headache for people trying to browse the site. We believe the issue may be some sort of indexing issue, caching issue, or a conflict of two or more of the extensions mentioned above.

Also, please write 'serp' at the top of your response. I apologize for this, but it does help weed out the people that do not bother to read.

Please ask me if you have any questions about this problem, or if you are interested and would like to see the problem on the site.

Thank you.