Customer Account Status Report showing mostly duplications (R-13)

Summary

The Customer Account Status Report shows about 90% of our customers twice.

Content

We are using the Customer Account Status Report in R-13 as our customer statement.  Not many of our customers want a statement, so we use this report to create a statement of the customer's outstanding balance.

The report lists almost every customer twice, including all of the invoice detail.

We cannot work out why any are duplicated, and we cannot work out why a handful are not.

It is easy enough to run the report for a single customer, or even a total report and search and edit to get the one customer we need to create a statement, so the functionality isn't really a problem.