stopping web app action shutdown kudu site unexpectedly

Question

when I stopped my web apps via web app overview page, I found the kudu site also failed to respond like below, after 20ish mins I was able to access the kudu site again. we did stop web app this action many times, but only few times we met this error, we also checked this document https://github.com/projectkudu/kudu/wiki/Full-stopping-a-Web-App in which it states stop action only stop web app, I wanted to confirm the situation we experienced is normal or abnormal, and what might have caused this error? thank you very much in advance.

updates: this is very important to us, usually we need to stop our web app and next use kudu site to do deployment, so kudu site shutdown unexpectedly would cause us more outage duration on our production env, this is not acceptable, thank you.