User report:
Strange bug in the iOS app: route lengths are under-reported. I believe this applies to all routes, but just as an example route #69840608 reports as 78.4mi in the iOS app, 85 3/4miles in the main webpage, or 85.72miles in m.cyclestreets.net. Cross-checking against Google maps and routes I've actually ridden suggests it is the iOS that is wrong and the other two correct.