Hello,
Thanks for the input!
At first glance, this does look like a potential bug, and I’d recommend reporting it on the official Highcharts GitHub repository:
https://github.com/highcharts/highcharts/issues. That’s the best place to raise issues like this, as it allows the development team to investigate and determine whether it’s a bug or expected behavior directly.
That said, based on the API documentation, it’s worth noting that the xDateFormat option specifically mentions formatting the “date in the tooltip header” (see:
https://api.highcharts.com/highcharts/t ... DateFormat) For scatter series, the x value isn’t included in the header by default - it’s part of the body of the tooltip. This might explain why xDateFormat doesn’t affect the x value in this case. Regardless, it’s still a valid point to raise, as the behavior could feel inconsistent compared to other chart types. Reporting it will let the development team decide if this should be addressed in a future update.
Let me know if you have more questions or need help customizing the tooltip formatting. Good luck with your project!
Best regards,