Modern UX Status Report only shows up to 25 tasks. This document explains how to display more than 26 task in the PDF.
Release : 16.0.3
It works by design that the Table widgets shows up to 25 rows per page (See "Configure Widgets in Canvas" under Additional Information for more information). If there are over 26 tasks and you would like to display them in the PDF, you need to add another Tasks Widget to the Status Report with an appropriate Task filter as per below.