[development] ghost nodes

[Lluís]

I am developing an access module and when rebuilding my node_access
table some nodes don't get rebuild. I don't know the cause but when
trying to analyse them with devel access node module I have discovered
that some of them are valid and some other show me the "page not
found" message.
So all of this have raised me 2 questions:
- ghost nodes: why nodes which are in {node} and {node_revisions} show
me a "page not found" message; is there any other table? how can I
track this?
- Why some nodes which get correct $grants when displaying them; don't
get them saved when rebuilding permission table?

Any hint is welcome. I ask both things together because I think they
may be related as I am working with custom nodes hardcoded by myself.

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