Milestone does not appear in PR sidebar anymore #2942

This happens when Refined GitHub is active, on all Pull Request pages.

1. In the discussion sidebar, click on the cogwheel next to the Milestone Heading
2. Add a Milestone to your PR.
3. Observe the event being logged in the PR body:
4. The sidebar, however, does not display the milestone:
5. Clicking on the cogwheel shows that we have in fact a milestone:

Here is an example where I saw this happening: https://github.com/Automattic/jetpack/pull/15103