Code quality widget shows "no change" at first but after reload the page it shows "XX degrations"

It’s quite easy to repro in my merge request.
As is shown in the screen shot below. One is before reload the page while the other is after.

I tried the official example here and it has the same problem: Add bad func to (!2) · Merge requests · Chris Liu / JH_java_example_project · GitLab

I’m using SaaS.