Thank you for providing screenshots and additional information about your setup.
I've tested the described scenario and I was able to reproduce the problem - it seems like the issue is reproducible only when using DateTimeContinuousAxis. I can confirm that this is a bug in the iOS implementation of our chart control. I have logged a Bug Report in our backlog about this behaviour. Here is a link
to the public item in our Feedback Portal where you can track the progress on the matter.
The only reasonable work around I can suggest you is to add and remove the series from code behind instead of setting the ItemsSource of the series to null.
Your Telerik points were updated to thank you for bringing this issue to our attention.
Our apologies for the inconvenience this causes you.
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