Swapping templates with a query loop block pattern causes flickering

[annezazu]

Using 6.5 RC 4 when swapping templates in the Post Editor, the preview of the template flickers when there's a query loop block on the post:

Screen.Recording.2024-03-29.at.11.54.44.AM.mov

Attached is the pattern I created and used (you'll need to create some posts with the category "block" to use it): query-loop-pattern.json

I couldn't replicate when using the Site Editor > Pages with 6.4.3 and swapping templates. I don't think this interrupts functionality for 6.5's release but it would be a solid fix for 6.5.1 if we can get something in place.

[colorful-tones]

This is a tricky one. The layout “thrashing” could be caused by some of these things

• lack of explicit ʼheightʼ or ʼwidthʼ for images. I wonder if there is a lack of reliance on ʼaspect-ratioʼ? 🤔
• overzealous animation or transitions
• rapid and repetitive reflows of the DOM

That 👆 is an incomplete list of possible starting points for debugging.

[creativecoder]

👋🏼 This issue is currently marked as "Todo" for a WP minor release. Noting that the release candidate for WP 6.5.3 is scheduled for May 2nd (next week). Someone will need to propose and merge a fix before that date for it to be included in WP 6.5.3. Otherwise we will need to punt it to a future release.

[greg-42droids]

WordPress 6.5.3 running Twenty Twenty-Four theme.
I have a different setup:

1. Add a Query Loop
2. Inside the Post Template, convert the group into a Pattern
3. Save the Post/Page
4. Try Swapping the Template and the page crashes. (generic React error)

I hope this helps a bit.

[Mamaduka]

@greg-42droids, do you mind creating a separate issue with reproduction details?

Thanks!