With Monarch, you get one row of data in the table for each instance of a detail template being found in your source report. (The only exception to this is when you use multiple column regions, but that's a whole other ballgame.) So if you have a report where there are no instances of the detail template, there won't be any rows of data in the table for that report.
You can solve this issue in a variety of ways - there are quite a few threads here about the "missing detail" problem. What works best will depend on your data, and how automatic you need the process to be. If you post some samples between CODE tags we'll be happy to have a look.