Consumer Reports is retesting the MacBook Pro to see how its battery performs. According to Apple, the organization's original results were highly variable due to a Safari bug. The MacBook Pro failed to receive a purchase recommendation from Consumer Reports because of the performance.
Apple says the group used a "hidden Safari setting" that caused an "obscure and intermittent bug reloading icons." Because of that software problem, the tests yielded variable battery life results.
The laptop has since been tested again, with Consumer Reports finding it "consistently" achieved the expected battery life.
Apple fixed the Safari bug with the most recent macOS Sierra beta.
Consumer Reports says it'll put the laptop through more testing and update its findings.