Exporting a batch with special characters ( e g é, å, ä, ö) for patron posts <firstname> and <surname> will cause them to be corrupted in the exported pdf - é becomes Ã©, å becomes Ä¥ and ö becomes Ã¶, for example. However, this doesn't always happen - _usually_ the first page comes out correctly (but not with things already incorrect).
Everything (apache2, MySQL, linux locale) is set to UTF-8, and label creator works flawlessly with these symbols. Going off an installation of the 3.12 liveDVD 3.12 (http://sourceforge.net/projects/kohalivedvd/) in Xubuntu.
Guessing the exporter uses a different standard, e g ANSI, which corrupts the text - but this is pure guesswork. :)
Extra information about the setup:
Template is for an A4 page, SI Centimeters, 29.7x21. Cards 7.7x4.8, Margins 2x2. 2 columns, 4 rows, gaps 0.5cm each.
Layout is layouted for front with guidebox on. It uses postscript points.
Text fields Field 1 houses: the bug-related information <firstname> <surname>, font Helvetica size 12, alignment center, X: 20 Y: 100.
Barcode number is printed, Code 39 (generated automatically in provided Katipo style), X:20, Y: 40
OS version ('uname -a'): Linux ubuntu 3.2.0-55-generic #85-Ubuntu SMP Wed Oct 2 13:43:27 UTC 2013 i686 athlon i386 GNU/Linux
Perl interpreter: /usr/bin/perl
Perl version: 5.014002
Perl @INC: /usr/share/koha/lib
MySQL version: mysql Ver 14.14 Distrib 5.5.32, for debian-linux-gnu (i686) using readline 6.2
Apache version: Server version: Apache/2.2.22 (Ubuntu)
Zebra version: Zebra 2.0.44 (C) 1994-2010, Index Data ApS Zebra is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. SHA1 ID: 419ad759807269fdfa379799a051ed3a551c6541 Using ICU
Running this in a virtual machine, VirtualBox.
Possibly related to Bug 2246
And Bug 8375
Someone might want to check the current validity of this bug as the fixes for Bug 8375 most likely corrected this problem as well.
This appears to be fixed in master.