Can you share your entire config.xml?
It's also possible that the setting is working correctly -- the preference only affects the webview itself. If your app has a scrollable element that uses native scrolling, that container can still bounce. Depending on how you've built your app, it's possible that would mean your entire app would still bounce -- that is, if your navigation bars and such were within a single containing element with scrolling enabled. As such, it might help to see your index.html or your app's HTML structure.
I think I have the same problem. you are describing at your comment that on the main screen its fine but the dynamic data still has dissallowOverscroll=false. How can I change this setting with js code or what?
DisallowOverscroll only works on the web view's scroll container. So if you have "overflow: scroll" and "-webkit-overflow-scrolling: touch" on a container, it will continue to bounce.
Without seeing your DOM structure, it's a little difficult to be of more assistance. Can you share what your DOM looks like with this page loaded? Share relevant styles as well.