I'm stumped. The x-axis in the chart above is fine — it's a category axis, and is rendering how I want it to.
The y-axis? I have no idea. It's being passed a duration in seconds (via an NSNumber instance) that's being formatted to a decimal of the hour. Have a look at the graph, though: the scaling between 0.4, 0.5 and 1.0 is completely off. I've tried setting ranges, fiddled with major and minor tick frequencies, set an anchor point — nothing is making the scaling make sense here.
What am I missing?