Query loop excerpt begins with ">"

[XiaoWXZ]

Description

I created a list of my latest blog posts using the Query Loop block. In the block editor, everything looks normal, but on the published page, the excerpt begins with ">".

Rather than "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed..."
It shows "> Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed..."

This symbol (>) obviously should not be present.

Step-by-step reproduction instructions

1. Create a WordPress site on the Twenty Twenty Four theme
2. Create a query loop block ("image at left")
3. Ensure there's an excerpt
4. Publish
5. Visit published page

Screenshots, screen recording, code snippet

No response

Environment info

• WordPress 6.7.1, Twenty Twenty Four Theme
• Safari on macOS
• Gutenberg 20.0.0
• PHP 8.4

Please confirm that you have searched existing issues in the repo.

• Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

• Yes

Please confirm which theme type you used for testing.

• Block
• Classic
• Hybrid (e.g. classic with theme.json)
• Not sure

[theMasudRana]

Thanks @jacobzymet for reporting the issue.
I was also able to reproduce the issue on my local setup. I'm adding a screenshot for more context.

[t-hamano]

Quote from this comment:

I haven't been able to investigate this in detail yet, but this issue should have been caused by #67272.

Temporarily deleting this changes fixes the issue, which means the problem must be somewhere in this newly added code.

[t-hamano]

Note: This issue can also be reproduced with the Latest Posts block.

Editor:

Front-end:

[Mamaduka]

Removed the "In Progress" label since the associated PR doesn't solve the issue.

[t-hamano]

Since this issue is likely to first appear in Gutenberg 20.0, i.e. the WP 6.8 release, I will add it to the project board.