Content missing in Deatailed Navigation

Dear Experts,

We are working on Portal NW 2004s SP 13. We've recently upgraded to SP 13. We found that there is unusual behavior in Deatailed Navigation. Under Deatiled Navigation there are some links which are accessed based group the remaining will be visible to all the users.

We have two different problems here

1) When we log in to portal we see some links and sometime links are automatically disappearing.

2) When we are adding a new page to any workset, it is not reflecting in the detailed navigation.

We have checked Portal Content part and everthing seems to be fine. the iviews are assigned to page, Pages are assigned to worksets.

Can someone tell why all of sudden this strange behavior happend. Any help will be appreciated on this issues.

Best Regards,

Satya