Steps to reproduce:
1) Open and run attached project. This is what i see:
2) Scroll down to the bottom of the QTableWidget, so the scrollbar is at the bottom.
3) Select the table item at the bottom, so it is highlighted.
4) Grab the last section of the vertical header, at the bottom, for resizing the last table item.
5) Drag the mouse a bit up for making the last row smaller.
Result: row 1 is not redrawn.
This is just one example, there is probably other ways to trigger it.