Find references doesn't find class methods of an instance created by "Type testing with pattern matching".
Let's say we have the following class:
public class Foo
{
public void Bar() {}
}
and the following part of code:
object fooObject = new Foo();
if (fooObject is Foo foo)
{
foo.Bar();
}
"Find References" does not work on the function call and "Find References" finds only a guess hit when used on the method definition.