You can observe this using the feature-demo by clicking on any async example, e.g. sse or http-kit, that indirectly accesses the session. This assumes there's something in the session, which you can do using the counter example. Once the error occurs, no future interaction with the web app is possible. This gist if from WF 9.0.2: https://gist.github.com/2334f5d2dc5f0e331a9c
The error has been observed with all versions of WF: 8, 9, and 10.