What worked for me was to point iPad browser to http://myappname.mendix.com/index.html Doing this resolved my problem. Thanks to everyone for your help.
I think you are affected by this iOS 6 POST caching bug
Edit: you probably are not, as you say you're on 4.2.2. What about pointing to index.html. Does that solve the issue?
Mike,
From the release notes:
Hosting an application with mobile forms
You can configure the web server (IIS, Apache, nginx) to redirect to index-mobile.html.
Maybe this is (automatically) set on your acceptance and production environment?
Would be worth filing a support request for this, I think.
I had the same problem and you can solve it by removing the index-mobile.html from your theme.
The way I solved this issue was to copy the index.html into the index-mobile.html in my theme.