Sometimes with very small values the hoverdata shows incorrect value probably due to some truncation, rounding, or formating. Hovering over the right left point shows 10 instead of ~0

Plotly.newPlot('myDiv',[{x: [0, 1],y: [1e-8, 1],type: 'scatter'}]);

Note that it works fine with for example

Plotly.newPlot('myDiv',[{x: [0, 1],y: [1e-8, 2e-8],type: 'scatter'}]);

when the y values does not span a big range.