Chartjs-Bar chart (chart.js) with only 2 points does not show one of the bars

The problem was apparently that the Y-axis started not at 0 by default. It’s possible to add an option for that:

options: {
            scales: {
                yAxes: [{
                    ticks: {
                        beginAtZero: true
                    }
                }]
            }
        }