Hi Ben,
Sounds intriguing. I'm not 100% sure what the issue is, but I have a couple of ideas of things to look at and think about.
1) Is the URL of the application publicly accessible? It would be neat if you could share that here.
2) Are you using a proxy? If so, verify that the proxy is working properly.
3) What happens if you change the initial zoom level in the code when the application loads?
4) What is different between the dev and deployment environments?
Hope this helps,
-Noah