S1185: FP when adding synchronized keyword to override method?

The rule raises an issue, when an overriding method adds the synchronized keyword. However, when adding a synchronized (this) block to the method no issue is raised. Consider the following snippet:

public class Unsynchronized {

  public void compute() {
  }

  public void calculate() {
  }
}

class SynchronizedOverride extends Unsynchronized {

  @Override
  public synchronized void compute() {
    super.compute();
  //^^^^^^^^^^^^^^^ raises an issue because only the super class implementation is called
  }

  @Override
  public void calculate() {
    synchronized (this) {
      super.calculate();
    }
  }
}

Should the rule not raise an issue when adding the synchronized keyword, the same way no issue is raised when adding the final keyword?

SonarJava version is 6.3.1, SonarQube version is 7.9.4