Class: I18N_Arabic_Glyphs, utf8Glyphs method renders some letters have tashkeel incorrectly with GD. A life example of the issue, available on the following URL:
Where the characters of the word لَا are rendered as لَلا in the image.
The string source is the MySQL database of Quran offered by http://www.qurandatabase.org.
The method printout the string without Tashkeel correctly.