PS. Digging through the codebase the possible values for sort_type appear to be date, number, lowercase, and string. I’m pretty sure lowercase is just like string but ignores case entirely, and the rest are self-explanatory
It’s possible that the sort function is having difficulty with this particular date format. In that case, there’s a way to pass a timestamp for each column’s value for sorting purpose.
The Col tag accepts an optional attribute value, which is used for sorting, separate from the displayed value (the formatted date).