If the RTL text continued to the next visual line, the positioning of the cursor is offset to the left, and that's only if the visual line is not the last line. The amount depend on the font somehow.

Visual line: each segment of the breaked line when word-wrap is on.

Text used:
"""
خشب
خشب خشب خشب خشب خشب خشب خشب خشب خشب خشب خشب خشب خشب خشب خشب خشب خشب خشب خشب خشب خشب خشب خشب خشب خشب خشب خشب 
"""

Screenshots showing the problem in the first and second line segments of the word-wraped line:  http://imgur.com/a/RwpNu (First one-word line and last segment are right)

Reproducible: Always