Noticed this happening in my games over the past few days.
Usually, one of the ways to finish off a LeBlanc combo is to land a chain on the enemy to proc Sigil of Malice. Often, LeBlanc players blink out, but the chain still goes out along its original cast direction (as shown in the first two examples.)
However, if used after R(W), the E-Snapback combo does not work. Instead the chain comes out from the return point.
If you watch carefully frame-by-frame between seconds 0:18 and 0:19 in the video example, the Ethereal Chains cast is started before the snapback occurs, but the chain only comes out after LeBlanc returns to her distortion marker.
Originally I thought it had to do with the double dash, however that theory was disproven by the second example in the video, where it clearly works fine if used after the regular Distortion. So I'd assume it's a bug between R(W) and E being cast in quick succession.
Please let me know if you have any information regarding this!
1) Use Distortion -> Mimicked Distortion -> Ethereal Chains -> Distortion Return in quick succession.
2) Observe the effect demonstrated in the video.