This seems like an oddly specific issue that I can't explain.
In SharePoint 2010.
As an FBA user publishing content, when I attempt to complete a page approval workflow task accessing the site via the 'Alternate Access Mapped' address (e.g. from www.site.com/_layouts/WrkTaskIP.aspx?) I get "validation errors" on the "Requested By" user details (despite the fact that I am infact currently logged in as that same user, who is a site owner and admin).
But if I access using the port number (e.g. Server:1000/_layouts/WrkTaskIP.aspx?, which obviously must be done on the local server machine which isn't an option for regular users) the details validate fine and I can proceed/complete.
(Note: using the Alternate Access Mapped address on the server machine still fails to validate)
I've been trying to do is set up a second FBA User database for a site collection. (Origional FBA users work fine. Logins, edits, publishing and approval, no problem).
I've created the new DB and added the new connection string and membership provider to the site, SecurityToken and Central Admin web.configs. Everything seemed to be working fine; creating new users works, users can log in, checkout, edit etc; and so I assumed everything was done correctly. Since getting the membership provider up and running this is the first, oddly specific, limitation of the new FBA user accounts.
Does anyone know why SharePoint can't validate a valid FBA user when accessing a workflow task via the sites alternate access mapped address (only)?