SYMPTOM:
In Strategy Developer 9.x, object boxes that overlap in a Report Services Document such as below,
Will cause data to be missing when exporting the document to a Microsoft Excel spreadsheet, as shown below:

CAUSE:
This occurs due to the fact that the overlapping objects exist in the document. The position of objects relative to other objects on a report services document affect the cells that they are placed in when exporting to Excel. When two objects are overlapping each other, exporting may cause the data from these two objects to be placed in a merged cell, and thus omit certain data.
ACTION:
Reposition the objects on the document so that they are not overlapping each other. Repositioning objects in a "trial and error" method is sometimes needed to obtain the desired Excel output.