[Bug] Strange behavior of property-search and org-tags-view

["Sven Bretfeld" <sven.bretfeld@gmx.ch>]

Hi all

Whenever I do a property-search (C-a / p) or an org-tags-view, some
org-buffers are touched and need to be saved again, i.e. they display
the ** flag in the status line and in Ibuffer.

It is always the same three files, that seemingly have changed (in fact,
they didn't change at all). They all belong to my org-agenda-files but
this contains many other files too, which remain unchanged. So, there
are two wired miracles involved:

1. What makes these three files so specially vulnerable?
2. Why does any file (apparently) "change" at all by a search operation?

I'm using Emacs 23.3.1 under Ubuntu 11.10 and org-mode 7.8.03 of the
sticky branch.

Thanks for help

Sven