title: Why does Magento randomly sort products in category list view and how can I fix that?
body: <p>For one of our clients, I manage a Magento store. The problem with this one is that, even though I have selected an attribute to sort on, the order of the products in the category list view is randomized within values.<br><br>
  Maybe this will make it a bit clearer:<br>
  Say I have sorted the category by the "bla" attribute.<br>
  Say 30 products have value "aa" on the "bla" attribute and 30 other products have value "ab".<br>
  Then Magento will first show all products that have value "aa" on the "bla" attribute and then the 30 products that have value "ab" on the "bla" attribute.<br><br>
  So far so good. However, within the "aa" products, the order keeps changing randomly. Even when still browsing the same category. Since there are sometimes 100+ products that have the same value on the "bla" attribute, this can lead to some product being displayed on the first page of the category list view, but then we encounter it again on the 3rd or even 4th page. Of course, Magento should remember the order in which the products are displayed to ensure that page navigation can never throw duplicate products at me, right?<br><br>
  So.. What's happening? Is this standard Magento behavior?<br><br>
  More importantly: what can I do about it?<br><br>
  Searching Google, Stack Overflow, etc. did not help me at all, so that's why I'm asking.</p>