Illustratr: Classic editor/classic block galleries aren't rendered with Gallery post format

[jp-imagines]

Quick summary

If you insert a gallery using either the classic editor or the Classic Block in the block editor, and set the post format to "Gallery," the gallery images do not display on the live post.

Steps to reproduce

1. Activate the Illustratr theme.
2. Create a new post in the Classic Editor.
3. Insert a gallery (Add Media > Create gallery > select images > Create a new gallery > Insert gallery).
4. Publish the post. The post format should automatically switch from Standard to Gallery.
5. View the post.

Alternatively:

1. Activate the Illustratr theme.
2. Create a new post in the block editor.
3. Insert a Classic Block.
4. Follow step 3 above to insert a gallery.
5. On the "Post" tab, change the Post Format to Gallery and Publish the post.
6. View the post.

What you expected to happen

The gallery should display on the live post.

What actually happened

No images are displayed. They're entirely missing from the HTML output.

Context

5271892-zd-woothemes

Simple, Atomic or both?

Simple, Atomic

Theme-specific issue?

Illustrator. Unsure if this affects other themes; unable to replicate on Twenty Twenty-One.

Browser, operating system and other notes

No response

Reproducibility

Consistent

Severity

Some (< 50%)

Available workarounds?

Yes, easy to implement

Workaround details

In the classic editor: after publishing, switch the Post Format back to Standard.

In the block editor: use a Gallery (or Tiled Gallery) block instead, or use the Standard Post Format.

[arunsathiya]

📌 HOUSEKEEPING

• Labels ✅
• Priority ✅
• Replicable on Core - No

📌 SCRUBBING

• Tested on Simple ✅
• Tested on AT ✅
• Tested on Self-hosted ✅

📌 FINDINGS/SCREENSHOTS/VIDEO

• I can reproduce only on Illustratr. A few other gallery post-supported themes that I tried, Sketch and Snaps, do not show this behavior.
• Cannot reproduce with Illustratr (downloaded from Illustratr WordPress.com theme page) on a WordPress.org site.

📌 ACTIONS

• Moving to themes repository.
• Thought this is related but re-reading it's a different issue: https://github.com/Automattic/themes/issues/1954

[vparkhere]

Ran into the same issue in 5362568-zen, using a Classic block and Gallery post format. Advised they use Standard post format as a workaround.