Layout Grid behaving weirdly with latest Gutenberg

[tellthemachines]

The Layout Grid resize handles are acting up when latest version of Gutenberg is enabled:

Screen.Recording.2023-05-26.at.1.44.38.pm.mov

This is most likely due to a change on the Gutenberg side, but it's hard to debug as I'm not really familiar with this block.

Also, trying to add Layout Grid to a post in my local dev environment with Gutenberg trunk results in the whole editor crashing with Uncaught TypeError: Cannot add property width, object is not extensible, making it even harder to get to the bottom of the issue 😅

[philbraun]

I get the same strange behaviour, and Layout Grids not being saved, but only when trying to use it inside the Site Editor in a Block Theme. Maybe the Site Editors Preview size setting conflicts with LG's Responsive Breakpoints settings?