Posted 14 September 2017, 12:09 pm EST
Hi Pavlo,
Thank you for reporting the issue and providing the sample. We are able to replicate the issue at our end and it looks like a bug. Hence, this issue has been escalated to the concerned team for further investigation with tracking id 274255. We will let you know as soon as we get any information on this.
As a workaround, currently, you can format X axis using rendering event and _xlables internal property. For your reference, please refer to the attached sample that implements the same.
Thanks,
Manish Kumar Gupta
2017/07/FlexChart_dateFormatting_withnullValue.zip