Query Loop & classic themes: when using the pagination dynamic behavior it breaks the styling of the whole page

[mdza8c]

Context and steps to reproduce

Steps to replicate the issue:

1. Go to any of the pages reported in the issue report/discussion.
2. Scroll down and click any other page in the page navigation block at the bottom.
3. Observe the issue. It persists when you go back to the previous page as well.

Browser console error reported:
Error loading url https://s0.wp.com/wp-content/plugins/gutenberg-core/v20.0.0/build-module/interactivity-router/index.min.js.map: HTTP error: status code 404,
net::ERR_HTTP_RESPONSE_CODE_FAILURE

Additional keywords for finding issues in console: Cannot access rules, cssrules, Source map failed to load, interactivity-router

Issue reported here: 9369470-zd-a8c
Issue discussed here: p1738699155661239-slack-C03TY6J1A

Site owner impact

Fewer than 20% of the total website/platform users

Severity

Moderate

What other impact(s) does this issue have?

No response

If a workaround is available, please outline it here.

On the Query Loop advanced settings, the Reload full page option can be turned on to not use this dynamic behavior when loading other pages.

Platform

Simple

[github-actions]

Support References

This comment is automatically generated. Please do not edit it.

• 9369470-zen
• 9364646-zen
• 9398996-zen

[Robertght]

Shared initial findings here p1738761479569779/1738699155.661239-slack-C03TY6J1A

[jartes]

📌 REPRODUCTION RESULTS

• Tested on Simple – Replicated
• Tested on Atomic – Replicated

📌 FINDINGS/SCREENSHOTS/VIDEO
Not all the CSS code is stripped on Atomic sites, and the issue goes away when the Gutenberg plugin is deactivated.

This seems to be happening only in the Canard theme.

📌 ACTIONS

• Triaged
• Keeping the low priority as there's an easy workaround for this one.
• Transferred to the themes repo.
• Added workaround and modified title.

👋🏻 @Automattic/t-rex Pinging you for this one, as it's coming from a customer report. Thank you!