Bars not rendering or disappearing while and after dragging

I've created a bar chart using `BarChartView`. The view displays work hours per day.
Unfortunately, some bars are not rendered at all - and others are disappearing while the whole chart is dragged.

Before the chart is shown the first time, it's zoomed to show only 7 bars at a time:

```
barChart.zoom(scaleX:ceil(CGFloat(dataSet.xMax - dataSet.xMin) / 7), scaleY: 1, x: 0, y: 0)
```

Then the view is animated, so the latest day is shown first:

```
barChart.moveViewToAnimated(xValue: dataSet.xMax, yValue: dataSet.yMin, axis: barChart.rightAxis.axisDependency, duration: 0.8, easingOption: .easeInOutSine)
```

This leads to the following result - so far, so good:


As soon as I drag the chart to the right, bars begin to disappear - only the value remains visible (notice the bar of Mo. 6th - it's gone):


Also all bars which are further left and therefore not visible immediately (because of the zoom) are not rendered at all. What I' doing wrong?

Reproduce the issue with BarChartView using the shown zoom and moveViewToAnimated calls, then drag the chart to the right while observing bars outside the initial viewport. Trace the rendering path during zooming, animation, and dragging; done means all bars remain rendered and visible values stay aligned after movement.

Written by the indexing model from the issue text.