I have a similar problem. I changed a class to call a different method in another class, but Xcode does not seem to update the call hierarchy for this.
Project contains Swift and Objective C code, but I don't see that that should matter. This issue is in code that is only Obj C.
Class1:
(NSString *)method1
(NSString *)method2
Class2:
[class1Instance method1]
After code change:
Class1:
(NSString *)method1
(NSString *)method2
Class2:
[class1Instance method2] // Start calling method2 instead
Using call hierarchy on "class1 method1" states that Class2 is still using it!
Using call hierarchy on "class1 method2" states there are no usages!