Immune lv 5 control effect but heroes still be silence lv 4 ?

What are control effect ? Why my heroes still get silence lv 4 from Valkyrie

And i don't know why Valkyrie of enemy almost 100% silence my Elsa heroes whenever enter the battle, even my team included Aoede with Immune lv 5 control effect, Elsa still be get silenced, wtf?