8 hours and 32 minutes is how long it takes to go from 3:38 pm to 10 after midnight? Perhaps the am/pm thing is also underspecified, so it chooses the shorter time delta?
That makes sense, ideally it should come back saying it's unsure but here's the best guess. I like the way WA explains it directly. The problem with these quick answers is you still can't blindly trust them unless they show their work.
