Thanks for getting in touch!
This is an issue in our chart's where we haven't cleared the chart property on the SChartAxis when removing it from it's old chart.
I have added this as a bug to our backlog where a member of the development team will investigate further.
A work around solution would be to set the "chart" property on your "axis" variable to nil before adding it to the chart again.
Let me know if you have any questions.