If you change the number of entries to show in member.pl, then select one entry to view, when you return to the list it reverts to just showing the default 20 entries. It should show the number of entries you had previously selected
I just tested this in the current development version and in 22.11: * Searched for 'all' patrons with an empty search * Changed per page setting to 10 * Clicked on an entry in the list, going to the patron account * Used the browser back button - setting remained I think we cannot save longer than this right now - there is no cookie or similar for this type of setting on the tables.