404 Error trying to view rich diff of png file in PR

When trying to view the rich diff of a png in a PR, I get 404 errors while logged in. In contrast, if I view the PR in Incognito Chrome, I do not get the error. PR: Updating Visual Diff Goldens for PR 1466 by github-actions · Pull Request #1477 · BrightspaceUI/core · GitHub

Seems like something is broken. Apologies if I’ve categorized this issue incorrectly. Attached screenshot. It just spins and eventually says “Sorry, something went wrong. Reload?”.

I also wasn’t able to view the rich diff, but my error report in Chome’s dev tool is slightly different:

Failed to load resource: the server responded with a status of 404 (Not Found)
Unchecked runtime.lastError: The message port closed before a response was received.
Unchecked runtime.lastError: The message port closed before a response was received.