Index: lib/redmine/export/pdf.rb
===================================================================
--- lib/redmine/export/pdf.rb	(revision 13458)
+++ lib/redmine/export/pdf.rb	(working copy)
@@ -51,6 +51,7 @@
 
         def SetFontStyle(style, size)
           style.delete!('B') if current_language.to_s.downcase == 'th' # FreeSerif Bold Thai font has problem.
+          style.delete!('I') if current_language.to_s.downcase == 'fa' or current_language.to_s.downcase == 'ar' # DejaVuSans Italic Arabic and Persian font has problem.
           set_font(@font_for_content, style, size)
         end