SYMPTOM:
In Strategy Web 9.3.1 when exporting a document to HTML, the detail header section gets truncated as shown below.

In the image above, the Day attribute returns more rows than the ones exported, but the export is truncated.
STEPS TO REPRODUCE:
Using Strategy Tutorial Project 9.3.1, perform the following steps:
CAUSE:
This is working as designed in Strategy Web 9.3.1. The height of the Detail Header section cannot be specified other than by specifying the layout property "Height can grow" or by manually dragging the limit of the next section, the Detail section, down. HTML exports are unable to perform the automatic calculation to define the height of the section during exporting, thus it takes the hard coded height property and cuts the export there.
ACTION:
In Design Mode, push the Details section down to the exact height required to accommodate all of the data during the export.