RestApi: Get user by username returns UserNotFound

Hello,

I've trying to extract users via the Rest API in Jive SBS 4.5.4.0. The database has about 31,000 users and most work fine, but 40 or so come back with UserNotFound.

Then it starts getting really odd. If I search for the user in the Jive Admin area (by username) and then try the api call again (e.g. http://www.domain.com/rpc/rest/userService/users/hans) the api returns the user.

I'm logging in with full admin permissions.

Any one have any ideas?

Thanks

Fran