Xcode 4.6 and Xcode 5 condition evolution behaviour

Question

Following statement works in xcode 4.6 and if block is executed

if (![fileManager fileExistsAtPath:FolderPath isDirectory:&isDirectory] && isDirectory)

But in xcode 5, it returned false and was going in else. After I had put both conditions in () it did work as expected. Actually it was silly mistake and that is how it should have been before as well, but somehow xcode 4.6 was giving true.

Correct statement : if (!([fileManager fileExistsAtPath:FolderPath isDirectory:&isDirectory] && isDirectory))

Any idea about why this behaviour difference in Xcode 4.6 and 5?