I’ve noticed a consistent issue with the builds in the new UI. I typically leave a build running in a browser tab and await the tab to turn green so I can deploy the build or take the next steps as needed.
In the old Circle UI, the tab with the running build would turn green and I would know that things were ready. Now, the build stays blue until I open the tab and refresh the page. In other words, the build is complete but the frontend doesn’t know it is until I do a manual page refresh.
I can provide example URLs for where I have seen this, if needed.
Although it wasn’t the exact same behaviour that you described, we’ve had a couple of reported issues involving that specific extension (uBlock Origin).
I’d suggest disabling it to confirm/rule out the cause.