Created attachment 309670 [details]
Program reproducing the bug

This bug is a logical continuation of bug 753772, which was closed as I did not properly explain the "real" problem.

Pango erroneously inserts spaces within a word when using the justify option for Hebrew. 

The attachment includes a program that when run generates the same text of three lines of Hebrew twice. At the upper half of the image with justification and at the lower half without justification.

As there are more than two words in each line, I don't expect any spaces to be inserted within a word. Yet in the second line of the layout Hebrew text, four spaces are inserted. In the second attachment image I have added red circles around these places.