$nav.root returning zero nodes

Am trying to fix an issue introduced by a content editor (who has recently left the organisation) which has broken the site navigation.

Basically a new folder has been created and made public; this folder replaced another which was archived (well, the navons were archived). The new folder seems to have been constructed properly and is live on the site. However, when the site is first loaded the navigation works as expected and the link to the new content can be seen, but as soon as another link is clicked the new content link disappears and can only be made visible by selecting the Home link again.

The problem appears to be when the site navigation is generated. The home page link finds the NavTree in the root OK and creates the navigation; but when other links are clicked the root for the navigation randomly changes to a descendant hence new navigation structure.

In the template that controls the navigation the following code sets the navigation root:

#rootlevel($nav.root) ##macro call

#macro(rootlevel $node)
<!-- Debug 1 node :: $node -->
#set($submenu = $node.getNodes(“nav:submenu”))
<!-- Debug 2 Size :: $submenu.size -->
#if ($node)
#foreach ($navon in $submenu)
#firstlevel ($navon)

When the macro is called $nav.root has 24 nodes; when it is called from another link the $nav.root has 0 nodes. I have even tried using the code below to force the NavTree node into the #rootLevel parameter, but this does not change things.

#set($rootGuid = $user.psoObjectFinder.getGuidById("1234"))	
#set($rootNode = $user.psoObjectFinder.getNodeByGuid($rootGuid))

Being new to Rhythmyx (we’re on version 6.7.0), and trying to support someone’s undocumented implementation doesn’t help the situation. Any help/pointers appreciated