Blog Posts Block - Featured Images Oversized and Overlap in the Editor

[donalirl]

Describe the bug
Images in the Blog Posts block (grid view) appear distorted in the editor, making it difficult to edit the site.

To Reproduce
Steps to reproduce the behavior:

1. Activate a block theme
2. Visit the site editor and edit the homepage template
3. Add a Blog Posts block
4. In the toolbar, choose Grid View
5. Ensure three posts are loaded and that each post has a featured image

Screenshots
Images are suddenly extremely large and pushed up against each other:

Expected behavior
I expected the editor view to show the images with correct spacing, like we see on the live site:

[philnick206]

Another report: 8582019-zd-a8c

[mxhassani]

Another one: 8622597-zen
Theme: Masu
Workaround: use query loop block

[masperber]

Another report here: 8663356-zd-a8c