Unstable - Getting 'Page not found' at the channel editor

[pcenov]

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Observed behavior

Observed while testing #5750:

I'm frequently getting a 502 error 'Page not found' at the channel editor.

page.not.found.mp4

Expected behavior

It should be investigating what's causing the error as it happens on various interactions without an obvious cause.

Steps to reproduce the issue

1. Sign in to Studio at Unstable
2. Create a new channel, import content and publish it.
3. Click the Share button, select the Submit to community library option and submit the form.
4. Navigate to a different channel and back to the current one.

Usage Details

• Studio Unstable
• OS: Windows 11
• Browser: Chrome, Firefox

[pcenov]

@radinamatic

[AlexVelezLl]

I suspect this may be related more to the import from channels flow as per some Percy errors like this. Does this also happen only after importing resources without publishing submissions?

[jaltekruse]

I don't know if this should possibly be filed as a separate ticket, but I am also getting intermittent "Page not found" errors when navigating the published english khan academy channel. That was recently updated, but if there is common code between the view-only channel tree navigation and the editable version for channels that you own then that recent update very well might not have an impact.

Sharing my screen recordings for the team if it is a useful repro case any/or may need to be broken off into a separate issue.

Screencast.from.2026-03-17.13-25-08.webm

Screencast.from.2026-03-17.13-24-11.webm

[rtibbles]

This probably points to it being a request timeout issue (as KA English is huge).

[AlexVelezLl]

Just got a 520 on the same endpoint on the production server too. This is a small channel. The requests are taking ~100ms, so I don't think it may be because of a timeout.