We are using here the project based authentication matrix. Crowd works fine for the global configuration of the auth matrix but when you
specify a crowd group for a specific hudson project it does not get recognized. You can easily test it like this:

1. create a group inside crowd
2. allow this group to login into hudson
3. configure hudson to use project based authentication
4. add the group to the global auth matrix of hudson only allowing general read and job read
5. add the same group to a projects auth matrix and give it build rights
6. add a user to the group inside crowd
7. try if you can do a build for the project you configured (here it doesn't work)