Queue times have returned to normal for those runner types. It appears to have only impacted high-volume GitHub Actions orgs and appears to be the fallout of the GitHub Actions outage reported earlier today: https://www.githubstatus.com/incidents/crd2y6xy6knn

We have implemented a workaround caused by the GitHub outage that is causing extended queue times for 8 & 16 CPU runners. We are monitoring the results and checking on queue times across the system.

We have identified the root cause as the GitHub Actions outage they had earlier. We have reduced the blast radius of long queue times to 8 and 16 core CPU runners for Ubuntu 24.04. We are working to bring that runner type back within normal queue times.

We've identified the cause of the issue, and are working on a fix.