iOS 11.2 with xCode 9.2
I have a chart with two data series and a legend. The chart lives in a view controller that is embedded in a navigation controller. I configured the navigation bar to hide itself when the phone it tilted into landscape mode: navigationController.hidesBarsWhenVerticallyCompact = true
When I tilt the phone the navigation bar is hidden as expected. However when I tap on the chart legend to turn off one of the data series I see the navigation bar re-appears. Screen shots attached.