Lucian's Relentless Pursuit removing slows again? [GAMEPLAY]

In a few games that my friends have played this patch they have told me that while playing Nasus, a Lucan can remove the Wither slow by dashing away from him. To replicate the bug that my friends and I have seen do as follows.

1. Have a Lucian and a Nasus on opposing teams.
2. Have the Nasus use Wither on Lucian.
3. Have the Lucian use Relentless Pursuit away from Nasus.

I unfortunately have no way to record this issue nor any screenshots to provide but I can assist in figuring out how this bug actually works.