This heatmap with "0" x/y category coords is broken

See https://codepen.io/ghfan/pen/EMMyKr where the only the `0` tick labels are showing.

First reported in https://community.plot.ly/t/wired-axis-in-heatmap-the-last-data-can-not-be-0-or-0-for-x-y-values/21308