I just deployed a custom account page from our sandbox to production instances. One the changes involved was to use
<apex:detail id="Account" relatedList="false"/>
and then reconstruct all of the related lists individually, for various reasons. One of them was so that we can control the number of lines returned for each list, using the pageSize attribute
<apex:relatedList list="Contracts" rendered="true" pageSize="5" />
This worked as expected in sandbox, but isn't working in production. It will allow for a higher number than the default, but not lower.
Is there something else which controls related list behaviour that I'm not aware of?
Edit: To clarify, our lists in production currently default to around 50, though it's not consistent between objects