Incorrect sorting order, why?

I’m trying to sort .Resources by but it gives me an incorrect sorting order (or at least when the groups are strings), if I sort by a param made of integers, e.g. .Params.weight, or if I change to integers rather than strings, then it gives me a correct sorting order.

Any ideas why my strings aren’t getting sorted right?

Sorting Template Code

{{ range sort .Resources "" }}
	{{ if isset .Params "group" }}
		<li>{{ .Title }} - {{ }}</li>
	{{ end }}
{{ end }}

Results (ee should be below dd):

    img0 - aa
    img1 - bb
    img2 - cc
    img4 - ee
    img3 - dd


title: "Images"
draft: false
- params:
    weight: 0
    group: "aa"
  src: ty1O7bs.jpg
  title: img0
- params:
    weight: 1
    group: "bb"
  src: 32csSRD.jpg
  title: img1
- params:
    weight: 2
    group: "cc"
  src: 0EVDFRa.jpg
  title: img2
- params:
    weight: 3
    group: "dd"
  src: 2GaiYCZ.png
  title: img3
- params:
    weight: 4
    group: "ee"
  src: Z5HzEpr.jpg
  title: img4