Lissandra Ultimate Bugs

I as a main am finding it very difficult to play her at the moment, because it seems her ult is failing to do what it is supposed to, which instantly freeze them. (I am aware of the delay between the cast and the actual tomb) but it seems as of lately it is failing to stop any actions. For example my most recent match I entombed a and she was in the ice already, but her ult still went off and killed myself and our ADC. Another big problem is for and . The ice will appear, the audio will go off and the damage will be dealt, if I cast it just before Fiora ult or yi Q goes off, they are not frozen and the ability still goes off, (however Yi will actually re-enter the tomb after the Q finishes, but it is pointless since we still took X amount of damage and then stun is rendered useless) Rito please help