Darius's pull VS Riven Bug [GamePlay]

This has been happening since the Mage patch , dunno if it was intentional or not , looked through patch notes did not find it but:

Every time Riven is using her Q which is the 3 Spell attack, if a Darius player tries to Pull during the animation of the second or third attack of Riven's spell , Riven does not get pulled only slowed for 1 second, again this did not happen before the Mage patch. This is the same as the Bug that used to happen with Riven's Shield and Vayne's push to wall. Riven would just slide off of the wall and here she would just slide out of it.