The analyzer has detected a suspicious code fragment with an 'if' statement whose both true- and false-statements are absolutely identical. It is often a sign of an error.
if (condition) result = FirstFunc(val); else result = FirstFunc(val);
Regardless of the variable's value, the same actions will be performed. This code is obviously incorrect and should have looked something like this:
if (condition) result = FirstFunc(val); else result = SecondFunc(val);
According to Common Weakness Enumeration, potential errors found by using this diagnostic are classified as CWE-691.
You can look at examples of errors detected by the V6004 diagnostic.