Two months ago I generated this heatmap https://plot.ly/~empet/14324, and at that time it displayed all data on hover.
It has been two weeks since something was changed in plotly.js, I guess, and now only the first row of data is displayed.
Today I ran again the notebook with Plotly 2.0.12, and Python 3.6, but the same odd behavior persists.
What could be the cause of this disappearance of tooltips?
Thanks for the report.