Home dashboard favourites and shortcuts wiped when the welcome banner is dismissed after a restart #54822

Describe the problem

After updating to Core 2026.10.1 (frontend 20260930.3, Home Assistant OS), my Home dashboard lost its favourites and shortcuts. I had dismissed the welcome banner long ago (welcome_banner_dismissed: true) and had 7 favourites plus 7 summary shortcuts. Right after the update restart the banner appeared again; I clicked it and used the dismiss action in the dialog. Afterwards the Home dashboard had no favourites and no custom shortcuts.

/config/.storage/frontend.system_data, key home:

• Backup taken a few minutes before the update: welcome_banner_dismissed: true, favorite_entities (7 entries), shortcuts (7 entries).
• After the dismiss click: only welcome_banner_dismissed: true.

I restored the key from the backup with frontend/set_system_data.

What I think happens

src/panels/home/ha-panel-home.ts:

• _showBanner only returns true when this._config.welcome_banner_dismissed is falsy. Since the stored value was true, the banner showing at all means the panel's _config was empty at that moment.
• _config is empty either before the initial frontend/get_system_data load finishes, or when that load is rejected: homeResult.status === "rejected" sets this._config = {} (only a console.error).
• _learnMore() then calls saveFrontendSystemData(connection, "home", { ...this._config, welcome_banner_dismissed: true }). With an empty _config this replaces the whole stored object, so favorite_entities, shortcuts, hide_welcome_message and hide_suggested_entities are deleted server side.

Suggested fix

Do not write the whole object from a possibly empty local copy. Options: do not show or act on the banner until the home config has loaded successfully, or re-read the stored value before merging in the dismiss flag, or have set_system_data for this key merge instead of replace.

Environment

• Core 2026.10.1, frontend 20260930.3, updated from 2026.9.4, restart right after the update
• Chrome on a Windows PC

What I could not determine

Whether the first home read failed or had just not finished when I clicked. I did not see an error message, and I do not have the browser console output from that moment, so the analysis above comes from reading the code.