Links to categories not working as expected

[rexxy]

The front page of our site is standard html. It has links to categories within the shop which is in a sub-folder.

 

example: "/catalog/index.php?cpath=103"

 

Sometimes the links on the html front page don't work correctly, it instead takes the visitor to the default home page at /catalog/index.php

 

Which is the same as putting in a cpath that doesnt exist like "/catalog/index.php?cpath=999"

 

However of course when clicking the category link from within the shop pages takes them to the correct category every time.

 

Strangely most times the links from the front page html work fine.

 

any ideas why a link from a static html page to a category within Osc doesnt always work as expected? Something do do with cookies or some authentication?