This is happening because you are using V2 of the lib and providing the backgroundColor as an array which means take the index of the color in the array and assign it to that bar, if there is no color don't use any.

So chaning your code to this will resolve the issue:

const data = {
      labels: Syear,
            datasets: [{
                label: 'Jumlah Korban Meninggal 5 Tahun terakhir',
                data: Sdead_total,
                backgroundColor: 'rgba(255, 99, 132, 0.2)',
                borderColor: 'rgba(255, 99, 132, 1)',
                borderWidth: 1
            },
            {
                label: 'Jumlah Korban Hilang 5 Tahun terakhir',
                data: Smissing_total,
                backgroundColor: 'rgba(54, 162, 235, 0.2)',
                borderColor: 'rgba(54, 162, 235, 1)',
                borderWidth: 1
            },
            {
                label: 'Jumlah Korban Luka Berat 5 Tahun terakhir',
                data: Sserious_woundTotal,
                backgroundColor: 'rgba(255, 206, 86, 0.2)',
                borderColor: 'rgba(255, 206, 86, 1)',
                borderWidth: 1
            },
            {
                label: 'Jumlah Korban Luka Ringan 5 Tahun terakhir',
                data: Sminor_injuriesTotal,
                backgroundColor: 'rgba(75, 192, 192, 0.2)',
                borderColor: 'rgba(75, 192, 192, 1)',
                borderWidth: 1
            }
          ]
    };