Config schema is incorrect

I have this error when updating Drupal core:

>  [notice] Update started: system_post_update_add_langcode_to_all_translatable_config
>  [notice] Processed 50 items of 1278.
>  [notice] Processed 100 items of 1278.
>  [notice] Processed 150 items of 1278.
>  [notice] Processed 200 items of 1278.
>  [notice] Processed 250 items of 1278.
>  [notice] Processed 300 items of 1278.
>  [notice] Processed 350 items of 1278.
>  [notice] Processed 400 items of 1278.
>  [notice] Processed 450 items of 1278.
>  [notice] Processed 500 items of 1278.
>  [notice] Processed 550 items of 1278.
>  [notice] Processed 600 items of 1278.
>  [notice] Processed 650 items of 1278.
>  [notice] Processed 700 items of 1278.
>  [notice] Processed 750 items of 1278.
>  [error]  AssertionError: assert($typed_config instanceof Mapping) in assert() (line 264 of /var/www/html/docroot/core/modules/system/system.post_update.php) #0 /var/www/html/docroot/core/modules/system/system.post_update.php(264): assert(false, 'assert($typed_c...')

I updated the schema + implemented hook_update_N

Confirming that patch in #5 solves that problem, but probably that should be a separate issue.

Patch in #5 fixes this issue for me as well.

I merged the patch in #5, but not 100% clear if that addresses the original issue here. The patch does resolve a fatal error when updating to Drupal 10.3, so wanted to make a new release with this fix. Feel free to reopen this issue if more work is needed.

The update hook in #5 does not work at all, there was no sequence key in the previous config schema. I'll update the patch, hopefully this hasn't been released yet.

Looks like it has been released. I'll add a new update hook instead of fixing the existing one.

The configuration form also hasn't been updated to work with the new config format. Kind of a shame that this has been released without proper testing.

This is already merged in 2.4.

@balaganb you didn't read my comment in #10, this issue is not actually fixed.

@mandclu would you mind having a look at this? The config form is still broken in the current release.