An Insights report with a ranking filter in addition to other filters is giving inaccurate data. For example, you are filtering for top 10 and receiving less than 10 results.
Insights report with multiple filters, including a ranking filter.
Cause and resolution
Filters are applied in order from top to bottom. This means that it is possible other filters are factoring into your results. To resolve this issue, ensure your ranking filter is last in the list.