SYMPTOM:
When a report with null values in cells of the right-most column is exported to a text file, data is missing in the last row. Consider the following example:

This Report contains Strategy Tutorial; the Manager attribute is in the rows and two filtered Units Sold metrics are in the columns to achieve null values. After export, the text file looks as following:

As seen in the above example, the semicolon from the last line is missing.
CAUSE:
This is a known issue with exporting to text files from Strategy Developer.
ACTION:
Strategy will continue to investigate and post updates as soon as they are available.