error when using as frontend module: name "mod-card" has already been used with this registry

My Home Assistant version: 2021.12.8

My lovelace configuration method (GUI or yaml): yaml

What I am doing: configuring card-mod as frontend module

What I expected to happen: no errors

What happened instead: This error in browser, plus a corresponding log entry:

Uncaught DOMException: Failed to execute 'define' on 'CustomElementRegistry': the name "mod-card" has already been used with this registry
    at http://homeassistant:8123/hacsfiles/lovelace-card-mod/card-mod.js?hacstag=190927524311:6:10674

Minimal steps to reproduce:

• Install card-mod 3.1.1 via HACS
• edit configuration.yaml to load card-mod as frontend module
• observe error message in browser console when reloading dashboard

# The least amount of code possible to reproduce my error
frontend:
  themes: !include_dir_merge_named themes/
  extra_module_url: /hacsfiles/lovelace-card-mod/card-mod.js
# End of code

Error messages from the browser console: Uncaught DOMException: Failed to execute ‘define’ on ‘CustomElementRegistry’: the name “mod-card” has already been used with this registry at http://homeassistant:8123/hacsfiles/lovelace-card-mod/card-mod.js?hacstag=190927524311:6:10674

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[thomasloven]

Should be gone now.

[shred86]

Unfortunately still receiving this same exact error. This is with using a lovelace design by matt0707.

card-mod was installed through HACS. The only slight difference I see is:

frontend:
  extra_module_url:
    - /hacsfiles/lovelace-card-mod/card-mod.js

This is defined in include/themes.yaml instead of the configuration.yaml file, but as far as I know, that shouldn’t matter.