This bug regards only synctex and is not directly targeted itexmac,
but synctex doesnt seem to have its own bug tracker.
Sometimes the synctex parser fails to do backward synchronization.
I've created an example for this in evince's bug tracker.
https://bugzilla.gnome.org/show_bug.cgi?id=630845
Synctex is not able to parse this pdf-file.
http://dl.dropbox.com/u/198449/main.pdf
http://dl.dropbox.com/u/198449/main.synctex.gz
Try to do synctex -o 52:300:200:main.pdf in the file to see that the synctex
parser does not perform the backward search.
The file was compiled with pdflatex with the following version.
pdflatex --version
pdfTeX 3.1415926-1.40.10-2.2 (TeX Live 2009/Arch Linux)
kpathsea version 5.1.0
Copyright 2009 Peter Breitenlohner (eTeX)/Han The Thanh (pdfTeX).
There is NO warranty. Redistribution of this software is
covered by the terms of both the pdfTeX copyright and
the Lesser GNU General Public License.
For more information about these matters, see the file
named COPYING and the pdfTeX source.
Primary author of pdfTeX: Peter Breitenlohner (eTeX)/Han The Thanh (pdfTeX).
Compiled with libpng 1.4.2; using libpng 1.4.3
Compiled with zlib 1.2.5; using zlib 1.2.5
Compiled with poppler version 0.14.0