Problem with range in combination with resources.FromString

I just ran into a strange behaviour and I am not shure where the mistake is. I would like to use resources.FromString and the string is generated within a range. First the working example:

{{ $number := slice "1" "2" "3"}}
{{ $string := slice "a" }}
{{ range $character }}
  {{ $string = $string | append "b" }}
{{ end }}
{{ $string = $string | append "c" }}
{{ $string = print (delimit $string "") }}
{{ printf "%T - %s" $string $string }}
{{- $targetPath := "css/generated.css" -}}
{{ $generated := $string | resources.FromString $targetPath | fingerprint }}
<link rel="stylesheet" href="{{ $generated.Permalink }}" integrity="{{ $generated.Data.Integrity }}">

The printed output is string - abbbc and the content of generated.css is abbbc. Ok, now I only change the range to use my categories .Site.Taxonomies.categories (there are 3 as well):

{{ $number := slice "1" "2" "3"}}
{{ $string := slice "a" }}
{{ range .Site.Taxonomies.categories }}
  {{ $string = $string | append "b" }}
{{ end }}
{{ $string = $string | append "c" }}
{{ $string = print (delimit $string "") }}
{{ printf "%T - %s" $string $string }}
{{ $targetPath := "css/generated.css" }}
{{ $generated := $string | resources.FromString $targetPath | fingerprint }}
<link rel="stylesheet" href="{{ $generated.Permalink }}" integrity="{{ $generated.Data.Integrity }}">

The printed output is again string - abbbc. Fine. However, the content of generated.css is just ac. So for some reason part of the string, which is generated with the range, gets lost in the resource.

Any suggestions?