[Not sure which component this actually belongs to].
Not sure when this occurred, but likely in the process of updating Jenkins to 2.263.1 (as well as all compatible plugins). If I visit a job in Jenkins without being logged in, the Test Result Trend graph never completes loading. See attached image.
If I login, the graph loads immediately. Seems to be the same issue with all jobs. I can see no errors in the Jenkins log related to this.
Global security settings, authorization are set to "Logged in-users can do anything" + "Allow anonymous access". I tried to temporarily change this to "Anyone can do anything" but that didn't make any difference.