Integration's custom-cards stopped working

Configuration Frontend
1

All customcards, which are bundled in integrations stopped working. Message like:

Custom element doesn’t exist: alarmo-card

appears. Integrations defined in configuration.yaml are unaffected. This started probably with HASS 2026.8.

Browser logs:

Uncaught (in promise) Error: Custom element not found: philips-shaver-card
gh create-element-base.ts:342 create-element-base.ts:342:22

Uncaught (in promise) Error: Custom element not found: smart-irrigation-zones-card
gh create-element-base.ts:342

I use several custom cards. Some are defined in configuration.yaml e.g.:

lovelace:
  resource_mode: yaml
  dashboards:
    lovelace:
      mode: yaml
      filename: ui-lovelace.yaml
      title: Overview
      icon: mdi:view-dashboard
      show_in_sidebar: true
  resources:
    #https://github.com/thomasloven/lovelace-card-tools
    - url: /local/customcards/card-tools.js
      type: module

    # #https://github.com/custom-cards/tracker-card
    # - url: /local/customcards/tracker-card.js?track=true
    # #- url: /customcards/tracker-card.js
    #   type: module

And some are integrated in integration (e.g. alarmo, smart-irrigation, philips-shaver-card). I am not using HACS, I install all integrations and custom cards manually.
I tried to restart HASS, change browser, hard refresh browser, anonymous mode, log checking…

2

As Alot Custom-Integrations Advertised “Breaking Changes” Updates with Specific Requirement for 2026.8, i Suggest you check Your Custom-Integrations ( Manually ), if they haven’t Released newly, like Max a week back, then you might need to Report Your Issues there, in each respective Integration :wink:
Funny that you didn’t thought of Checking Your Manually Installed integration first though

3

If the integration bundles with adding to extra_moduke_url (like UI Lovelace Minimalist) then the cards may not work unless they handle waiting for Frontend to be ready such that when they call customElements.define they are adding to the Hone Assistant poly filled customElements. In such a case turn off bundling if possible and load directly via HACS

If it’s the integration itself loading a Frontend resource then it will likely be suffering the same and the resource needs to handle the same definition delay.

4

I have found a solution. Problem was in yaml defined lovelace resources. After migrating them to UI (Dashboards->Resources) was problem solved