[Bug]: Error: Failed to execute 'define' on 'CustomElementRegistry'

[scw2wi]

Description

The following error message seams to be coming from this card.

Error:
Failed to execute 'define' on 'CustomElementRegistry':
the name "base-custom-feature" has already been used with this registry.

Environment

- OS: [Windows 11]
- Browser: [Edge]
- Home Assistant Version: [2025.10.4]        
- Tabbed Card Version: [0.3.3]

Reproducible configuration

- type: custom:tabbed-card
    view_layout:
      grid-area: tabs
    styles:
      "--mdc-theme-primary": darkorange
    options:
      defaultTabIndex: 0
    tabs:
      - attributes:
          label: April
        card:
          type: custom:decluttering-card
          template: irrigation_schedule_card
          variables:
            - MONTH: apr
      - attributes:
          label: Mai
        card:
          type: custom:decluttering-card
          template: irrigation_schedule_card
          variables:
            - MONTH: may
      - attributes:
          label: Juni
        card:
          type: custom:decluttering-card
          template: irrigation_schedule_card
          variables:
            - MONTH: jun
      - attributes:
          label: Juli
        card:
          type: custom:decluttering-card
          template: irrigation_schedule_card
          variables:
            - MONTH: jul
      - attributes:
          label: Aug
        card:
          type: custom:decluttering-card
          template: irrigation_schedule_card
          variables:
            - MONTH: aug
      - attributes:
          label: Sep
        card:
          type: custom:decluttering-card
          template: irrigation_schedule_card
          variables:
            - MONTH: sep

Additional context

No response

[kinghat]

is it reproducible with built in cards that come with home assistant? also, can you show me where the error is coming from to see why you think its coming from this card?

[scw2wi]

Sorry, I forgot to paste the hole error message.

After every start from HA I can see in /config/logs the following message where tabbed-card is shown, that was the reason why I think it could come from this card. But since also custom-card-features are shown, it can also come from another module.

Protokolldetails (FEHLER)
Logger: frontend.js.modern.202510014
Quelle: components/system_log/init.py:331
Erstmals aufgetreten: 9. November 2025 um 17:46:04 (2 Vorkommnisse)
Zuletzt protokolliert: 9. November 2025 um 17:46:06

Uncaught error from Edge 142.0.0.0 on Windows 10 Error: Failed to execute 'define' on 'CustomElementRegistry': the name "base-custom-feature" has already been used with this registry A.define (node_modules/@webcomponents/scoped-custom-element-registry/src/scoped-custom-element-registry.ts:180:12) a.define (/hacsfiles/tabbed-card/tabbed-card.js:63:109) /hacsfiles/custom-card-features/custom-card-features.min.js:8:6623 __decorate (/hacsfiles/custom-card-features/custom-card-features.min.js:1:103037) 616 (/hacsfiles/custom-card-features/custom-card-features.min.js:1:116450) webpack_require (/hacsfiles/custom-card-features/custom-card-features.min.js:8:8543) /hacsfiles/custom-card-features/custom-card-features.min.js:8:10528 /hacsfiles/custom-card-features/custom-card-features.min.js:276:14100 /hacsfiles/custom-card-features/custom-card-features.min.js:276:14104

[kinghat]

is it reproducible with built in cards that come with home assistant? can you take a screenshot of the card showing the issue?

[scw2wi]

The card itself is working fine, I only get this reproducible error on every reboot.

In the past I got a lot of errors I didn't care about.
Now I handled all my errors, mostly by adding default values for case of unavailable sensors.
But this error here I could not handle, because It's not coming from my own code.
That's the reason I reported it here.

If you are quite sure it's not coming from this card, you can simply close this issue.
As I said, it's just an error message at startup that I can simply ignore.

[kinghat]

The card itself is working fine, I only get this reproducible error on every reboot.

In the past I got a lot of errors I didn't care about. Now I handled all my errors, mostly by adding default values for case of unavailable sensors. But this error here I could not handle, because It's not coming from my own code. That's the reason I reported it here.

If you are quite sure it's not coming from this card, you can simply close this issue. As I said, it's just an error message at startup that I can simply ignore.

i wouldnt worry about it if your cards are all functioning properly. im also getting that error with a different card:

Uncaught error from Firefox 144.0 on Linux Error: Failed to execute 'define' on 'CustomElementRegistry': the name "remote-button" has already been used with this registry 68965/</A.prototype.define (node_modules/@webcomponents/scoped-custom-element-registry/src/scoped-custom-element-registry.ts:180:12) xe/a.define (/hacsfiles/tabbed-card/tabbed-card.js:63:109) 837/i/< (/hacsfiles/android-tv-card/universal-remote-card.min.js:11:277661) y (/hacsfiles/android-tv-card/universal-remote-card.min.js:11:324316) /hacsfiles/android-tv-card/universal-remote-card.min.js:11:328594 /hacsfiles/android-tv-card/universal-remote-card.min.js:44:18471 /hacsfiles/android-tv-card/universal-remote-card.min.js:44:18475

tabbed-card needs updated to use the new web components system that ha moved to. hopefully a winter project.

[scw2wi]

Perfect, so I know this error message can be ignored. Thanks for taking care.