Adjustments to the source language are not included in the translation

@handkerchief I can confirm, that this is an issue with core ^10.1.

As a temporary fix:
e.g. after deleting the block in source language (DE), switch to Layout Builder in the translated language (EN) and save the Layout Builder before you start editing the blocks. After saving the EN Layout Builder you should see your adjustments.

I updated ticket priority because this breaks the symmetrical behavior.

Can confirm this issue. This breaks the editing experience.
On the other hand, in the node view this issue is not present so it does not break the viewing experience.

Seems like a big issue to me.

Can also confirm that the workaround in #2 works. (saving layout builder page of translation)

Another update on this:

This seems to be an error with the layout_builder tempstorage.
In our case, we had no concurrent editing and all languages should be in sync.
Because of this, I was able to implement the patch I attached here.

In this patch I added a presave functionality to clear the LB tempstore and thus display the correct layout in de Layout Builder page.

Added an updated version of the patch since there was a bug with non existing section storage.

This is probably the same problem that was reported at https://www.drupal.org/project/layout_builder_st/issues/3222423 🐛 Layout translation form reports unsaved changes and becomes stale Needs review , when layout translation form reports unsaved changes and becomes stale.
Patch #2 of that issue worked for me.

Thank you for pointing this out! I can confirm that the patch from https://www.drupal.org/project/layout_builder_st/issues/3222423 🐛 Layout translation form reports unsaved changes and becomes stale Needs review is fixing this issue. I guess because 3222423 is created three years ago - this issue is a duplicate.

@LRoels thank for your time and effort, too.