data-listing-date-modified-sort="NaN"

Bug description

When running quarto preview or quarto render, the listing page generates HTML that contains data-listing-date-modified-sort="NaN"

Steps to reproduce

Create a new blog:

quarto create project blog myblog

Preview the blog:

quarto preview myblog

Expected behavior

This should produce a valid value for the HTML attribute.

Actual behavior

The following HTML is produced:

<div class="quarto-post image-right" ... data-listing-date-modified-sort="NaN" ... >

Your environment

MacOS Sonoma 14.5

Quarto check output

 quarto check
Quarto 1.5.56
[✓] Checking versions of quarto binary dependencies...
      Pandoc version 3.2.0: OK
      Dart Sass version 1.70.0: OK
      Deno version 1.41.0: OK
      Typst version 0.11.0: OK
[✓] Checking versions of quarto dependencies......OK
[✓] Checking Quarto installation......OK
      Version: 1.5.56
      Path: /Applications/quarto/bin

[✓] Checking tools....................OK
      TinyTeX: (not installed)
      Chromium: (not installed)

[✓] Checking LaTeX....................OK
      Tex:  (not detected)

[✓] Checking basic markdown render....OK

[✓] Checking Python 3 installation....OK
      Version: 3.11.2
      Path: /Users/hodgesmr/.virtualenvs/quarto/bin/python3
      Jupyter: 5.7.2
      Kernels: python3

[✓] Checking Jupyter engine render....OK

[✓] Checking R installation...........(None)

      Unable to locate an installed version of R.
      Install R from https://cloud.r-project.org/

Start by running quarto create project blog myblog, then quarto preview myblog or quarto render and inspect the generated listing HTML. Trace the listing-generation entry point responsible for data-listing-date-modified-sort; done means the attribute contains a valid value instead of NaN.