Sorting date not working as expected

exon02

I'm having trouble with the sorting of a date column.
It seems that it only sorts the day but not the year.

I've made a jsfiddle with the issue if you sort the startdate there are records of 2019 between records of 2020
https://jsfiddle.net/obswu4tk/

exon02

Found the solution on https://stackoverflow.com/questions/36984554/sorting-date-in-datatable