Fiora W Not Stunning When Blocking Disables

As the title says Fiora's W is not properly stunning champions when they try to disable her. Game example against Yasuo, Nami, Anivia, Tahm Kench, and Vayne. Fiora would block the damage and ability and the enemy champion would not be stunned when Yasuo using Tornado, Anivia using Q(flash frost), Nami using Q bubble or R ultimate, Vayne using condem and Tahm using Q or W with three stacks on.