"Open at login" settings are ignored
Your workaround is the beginning of the right problem analysis.
Verify that the ACL on ~/Library/Preferences are correct.

Let's say your user name is BOB.
Within Terminal or xterm type:


$ cd ${HOME}/Library
$ ls -del Preferences
drwx------+ 9 BOB  staff  6324 Jul 31 14:10 Preferences
 0: group:everyone deny delete
 1: user:_spotlight inherited allow list,search,readattr,readextattr,readsecurity,file_inherit,directory_inherit
$

If your ACL aren't exactly as above, and most notably completly empty,
check that your NFS server is correctly configured to manage ACL.

On your Mac which is the NFS client, check with the mount command that the noacl option isn't turned on.