When restoring a WP autosave (with yellow banner button on top of editor page), all blocks renamed classes are back to automatically generated class names, and all associated virtual classes are replaced with “removed” (and all associated style is lost).
NOTE: Hopefully, I could restore a previous WP page revision and everything was back, so I only lost a few minutes of work, but that doesn’t inspire trust
Indeed, I can confirm this is happening when restoring the backup. This is because Gutenberg does not signal at any stage that it is replacing the post content, thus our renaming function comes into play thinking that the replaced blocks are duplicates of the existing ones.
