Block Grid does not render block editor thumbnails

[asawyermarathon]

Which Umbraco version are you using? (Please write the exact version, example: 10.1.0)

14.0.0

Bug summary

Block Grid does not render block editor thumbnails.

Specifics

Block Grid does not render block editor thumbnails. I took a video.

https://github.com/umbraco/Umbraco-CMS/assets/87725234/11cc5a73-beaa-487c-8c67-c9f047fff4dd

Steps to reproduce

1. In settings, create a block grid data type and add a block editor, specify a thumbnail
2. In content, when adding an item to the block grid content, no thumbnail is rendered

Expected result / actual result

Block Editor thumbnails should be rendered

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This item has been added to our backlog AB#41791