Backup/Snapshot can't be deleted

[no0ner]

The problem

After the update to 2021.9.0 I'm unable to delete backups/snapshots via Supervisor/Backups.
Folder should be /backup/ instead of /backups/ and the file extension (.tar) is missing (see logs).

What is version of Home Assistant Core has the issue?

2021.9.0

What was the last working version of Home Assistant Core?

2021.8.8

What type of installation are you running?

Home Assistant Supervised

Integration causing the issue

No response

Link to integration documentation on our website

No response

Example YAML snippet

No response

Anything in the logs that might be useful for us?

2021-09-02 09:33:36 ERROR (MainThread) [homeassistant.components.hassio.handler] /backups/d9d17ba4/remove return code 404
2021-09-02 09:33:36 ERROR (MainThread) [homeassistant.components.hassio] Failed to to call /backups/d9d17ba4/remove -

Additional information

No response

[ludeeus]

This was fixed in Supervisor 2021.8.1 👍

[no0ner]

Hmmm, I'm on supervisor-2021.08.1 already but I'm not able to delete the backups anyway.

[ludeeus]

Clear your browser cache, this was a frontend issue

[no0ner]

Clearing the Chrome cache didn't work so I installed Firefox and it also didn't work. Any other ideas/tips?

[ludeeus]

Not really, the issue is that it adds /remove to it, and that was fixed in the frontend version that is included in 2021.8.1

[no0ner]

I also tried restarting the supervisor, core and the host system but still get the same error.

[ludeeus]

Could it be that you are behind cloudflare and have not cleared cache there?
If you use IP:port and not any host name, is it the same?

[no0ner]

I'm connecting to HA via VPN (WireGuard) using the IP:port. I'll check it without VPN when I'm at home later. Thanks so far!

Edit:
I just realised it fails when I delete it within the list view but works when I click on the backup title and use the dot-menu in the modal that opens.

[ludeeus]

AH! That might be an issue still

Edit: confirmed https://github.com/home-assistant/frontend/blob/dev/src/data/hassio/backup.ts#L157