Older Gallery Blocks with 2+ columns appear in 1 left-aligned column on frontend

[liviopv]

Quick summary

Images inserted within a Gallery Block are overlapping, as if the frontend was not properly rendering the spacing and alignment of the grid.

It's most visible in the default Gallery and the Stacked variations, but it could be affecting other styles as well.

Example:
https://liviofree.wordpress.com/2023/10/31/galleries-test/

I could only reproduce on a Simple Site

Steps to reproduce

1. Activate a Classic Theme, like Twenty Twenty
2. Add a Gallery Block
3. Add a few images to the Gallery
4. The images will overlap

What you expected to happen

The Gallery should be rendered as shown in the editor

What actually happened

The images are incorrectly aligned and spaced in the frontend

Impact

Some (< 50%)

Available workarounds?

No but the platform is still usable

Platform (Simple and/or Atomic)

Simple

Logs or notes

Reproduced on
Gutenberg: v16.9.0
Editing Toolkit: 4.2070
WP AMP:
CoBlocks: 2.18.1-simple-rev.4

Unable to reproduce on Atomic and local site running GB 16.9

[cuemarie]

Escalation thread: p1698766181837769-slack-C02FMH4G8

[simison]

@liviopv have you replicated un-proxied? Or do we have customer reports?

I'm able to replicate only proxied. Unproxied Firefox/Chrome/Safari all work. My test post https://simisontestingfreeflow.wordpress.com/2023/10/31/33/

When I sandbox, gallery again works. Tested through versions of Gutenberg: 16.7.1, 16.8.0, 16.9.0-RC1. All worked while sandboxing.

Looks also that simple sites run Gutenberg 16.8.1. Tested with classic Hever theme.

[cuemarie]

📌 REPRODUCTION RESULTS

• Tested on Simple – Replicated

📌 FINDINGS/SCREENSHOTS/VIDEO
Like the above notes, I can only replicate this when proxied. Unproxied, the Gallery Block behaves as expected.

Simple Site tested:

Theme: Twenty Twenty
Gutenberg: v16.9.0
Editing Toolkit: 4.2070
WP AMP:

rmPup1.mp4

📌 ACTIONS

• Triaged
• Lowering priority based on findings and advice here: p1698770819261839/1698766181.837769-slack-C02FMH4G8