[Plugin: Members List Plugin] profile update > search results discrepency

I am using User Meta Pro for custom fields for users profiles… when a user is created and most fields are filled… they do show up in search… if I add content in another field that was previously empty, and save… the user is still searchable, but the new data filled in does not display in the search results *if search “by last name” via the alpha menu… but if searched with the “all fields” field, the additional data displays… any idea why?

http://wordpress.org/extend/plugins/members-list/