Can you have a try with the attached jettty.zip.txt in previous reply to see if you reproduce it?
It's used to simulate my APP, you can just download it and change to jetty.zip and unzip it.
There is a manifest file along with a war file and jetty runner.
You can push it to a bosh lite VM and you should see the issue.

In this sample, actually there is nothing special configured for jetty.
we just run it like "java -jar jetty-runner.jar --port $PORT testId.war" in the container.

My APP is quite large and has many dependencies, which make it not easy to post somewhere.