Code coverage do not include every file to the final coverage

In my simple app I have a few files that are tested by unit testing and uitesting.

I am pretty sure that I testes EVERY line in WLLoginViewController. The test passed, but it is not considered as 100% in code coverage for that file. Sometimes when I restart Xcode, run app again, clean app, hard clean app. Do some accidental things, it works. But run tests once again, and again it is not considered. Why? Any ideas how to fix it? Is it a bug?