When a textbox cannot fit on the current page and its Style.VerticalAlign is not set to Top, the textbox is pushed to the next page, although its KeepTogether property is set to false and its Value is null or empty.

This scenario usually happens when a textbox in a table grows vertically because the table contents also grow - it might be another nested table or any other data item. The solution is to either set the visibility of the textbox to false or set its Style.VerticalAlign to Top.