What’s your SonarQube server version? If you’re not sure, you can check the page footer.
Do you have anything “helpful” on your network between SonarQube and Jenkins that might be interfering?
Could you check your server logs logs and see if the slowdown you’re seeing in analysis correlates with anything in particular on the server side? I would expect this to show up - assuming anything does - in the ce.log or web.log.
Your server logs won’t do me much good since I don’t have the timestamps of the slowdowns. I need you to check them to see if you can correlate anything unusual at the server with a slowdown in Jenkins.