SIGSEV when adding _index.md to sections

Hugo crashes for me as soon as I add an _index.md file to a section directory. The content of the file does not matter, even an empty file leads to the crash. I’m on Mac, current home-brew build:
hugo v0.103.1+extended darwin/amd64 BuildDate=unknown
Log:

DEBUG 2022/09/19 22:16:44 creating alias: /teleskope/page/1/index.html redirecting to http://localhost:1313/teleskope/
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x8 pc=0x513b0d1]

goroutine 138 [running]:
github.com/gohugoio/hugo/hugolib.(*pageState).getLayoutDescriptor.func1()
	github.com/gohugoio/hugo/hugolib/page.go:416 +0xf1
sync.(*Once).doSlow(0x0?, 0x5d52afb?)
	sync/once.go:74 +0xc2
sync.(*Once).Do(...)
	sync/once.go:65
github.com/gohugoio/hugo/hugolib.(*pageState).getLayoutDescriptor(0xc0001e7830?)
	github.com/gohugoio/hugo/hugolib/page.go:405 +0x7d
github.com/gohugoio/hugo/hugolib.(*pageState).resolveTemplate(0xc0001e7830, {0x0, 0x0, 0xc002e552c0?})
	github.com/gohugoio/hugo/hugolib/page.go:443 +0x1cd
github.com/gohugoio/hugo/hugolib.pageRenderer(0x4ca1585?, 0xc0005b4d80, 0xc0000b67d0?, 0x4ca1506?, 0xc0000b6798?)
	github.com/gohugoio/hugo/hugolib/site_render.go:125 +0x113
created by github.com/gohugoio/hugo/hugolib.(*Site).renderPages
	github.com/gohugoio/hugo/hugolib/site_render.go:74 +0x108

terms.html (modified from anananke theme - but the original leads to the same problem):

{ define "main" }}
  {{ $data := .Data }}
  <article class="cf pa3 pa4-m pa4-l">
    <div class="measure-wide-l center f4 lh-copy nested-copy-line-height nested-links {{ $.Param "text_color" | default "mid-gray" }} {{ $.Param "post_content_classes" | default "bg-near-white" }}">
      {{ .Content }}
    </div>
  </article>
  <div class="mw8 center">
    <section class="ph4  {{ $.Param "secondary_text_color" | default "mid-gray" }} {{ $.Param "post_content_classes" | default "bg-near-white" }}">
      {{ range $key, $value := .Data.Terms }}
        <h2 class="f1">
          <a href=" {{$value.Page.RelPermalink }}">
            {{ $value.Page.Title }}
          </a>
        </h2>
        {{ range $value.Pages }}
          {{ .Render "summary-with-image" }}
        {{ end }}
      {{ end }}
    </section>
  </div>    
{{ end }}

Taxonomy definition in config.toml:

[languages]
  [languages.de]
    title = "Astrofotografie Torben van Hees"
    weight = 1
    contentDir = "content/de"
    [languages.de.taxonomies]
      Kategorie = 'Kategorien'
      Schlagwort = 'Schlagworte'
      Kamera = 'Kameras'
      Teleskop = 'Teleskope'
      Montierung = 'Montierungen'
      Objekt = 'Objekte'
      Filter = 'Filter'