[eluser]OverZealous[/eluser] @lexusgs430
First, you are using the method wrong. Read the docs again. The first parameter is the list of IDs to exclude. The second parameter is the column to use DISTINCT on.
Before submitting a question, you should look at the queries being generated. There's some good tips for debugging in the troubleshooting guide, at the top. They walk you through some basic debugging steps. You probably would have easily seen that the query being generated was not what you expected.
