Do you have "all" selected or do you perhaps have one of the other three categories selected. For example, there are 2 pages for the items achievements but it will still show 2 pages if you selected "earned," "in progress," or "retired" even if there is only one page.

that is really weird. Few more quick questions. Are you getting to your achievements from your menu or your profile? And when you get this, Are you going there straight away or do you click any links before?