Since upgrading to Home Assistant 2025.6 I noticed a problem visiting on the local url: https://homeassistant.local:8123, Music Assistant, Settings etc. Normal dashboards are accessible. Accessing these pages using an external URL https://xxxxx.duckdns.org does work. This problem does not occur when using the web interface. Workaround for this issue is deleting the local URL from the server settings in the app. Happens both on iPad and iPhone.
Probably a frontend cache issue. Don’t use Apple, but the setting should be found in Companion app settings >> debugging* >> reset frontend cache.
*In Android, this option is called Troubleshooting, so search for that if you can’t find debugging listed.