Heatmap: pointPadding with yAxis.reversed is not working correctly

[raf18seb]

Expected behaviour

Points should have a correct 10px padding in all directions like in a normal chart: https://jsfiddle.net/BlackLabel/32h6mpor/

Actual behaviour

Points have wrong pointPadding when yAxis.reversed: true: https://jsfiddle.net/BlackLabel/fgyzkce8/

Product version

Highcharts 10.3.3

Worked fine in 8.0.4, broken since 8.1.0. Unable to bisect.

[hubertkozik]

There is also a problem with setting xAxis.reversed to true, like in this demo: https://jsfiddle.net/BlackLabel/vkz3fxa6/ Despite setting pointPadding the points don't have proper padding.