I already reported the problem with LeBlanc's Ult, and noticed that the bug is still here after several months, and it's very annoying to waste her ult this way.
I already noticed that when I Q someone which is too far, I walk to him, and if I use W to dash toward him, LeBlanc keep in mind Q to launch it once she is in range, even after using W.
The problem is it's the same thing with R. Sometime, I use quickly Q then R, but it happens that the enemy starts to run away and then isn't in range for R. So I dash toward him with W... But of course, he remembers that I asked to use R, and since R became distortion with W... then LeBlanc uses it after Dashing once.
Sometime, she just come back in safe, and sometime, she dash twice forward, and then put me in a bad position.
In case my explanations aren't clear, I made a video: http://www.youtube.com/watch?v=nrK_l3432oY