[Accessibility] Reading order is not as expected while using a screen reader on Heatmap.

[magdalena-gut]

Expected behaviour

Reading should start from the first point (0,0) and continue in the correct order.

Actual behaviour

The screen reader ignores the first square at (0,0), starts at square (0,1), and continues reading in the correct order. Once it hits the last square, it goes back and finally reads the first square as though it is the last data point in the series.

Demo

https://www.highcharts.com/demo/heatmap

Product version

Highcharts 9.3.2

Affected screen readers

VoiceOver
(NVDA with Google Chrome and Firefox work correctly.)

[oysteinmoseng]

Internal note: Caused by #13049

[oysteinmoseng]

Will close this as duplicate, follow #13049 for updates