Every time you click inside a textbox it creates a sibling input element. Also, the initial textbox's value is never set.
Recreation Steps: Go here -> http://jquerymobile.com/demos/1.3.0-rc.1/docs/forms/textinputs/ In Chrome or Firefox, right click the first textbox and choose "Inspect Element". Now left click inside the textbox repeatedly. You will see that every time you click, an input element is created. Also, the initial textbox never has its value set.
I added a panel to my page and I soon noticed that the popups were not working properly. I narrowed down the problem to the combination of properties data-display="overlay" data-position-fixed="true" of the panel making the popups not show. If you remove either one of those properties, the popups work fine.
Here is the html http://jsfiddle.net/AMWga/. Notice it works fine in a browser, but not on mobile devices.
Tested using: jQuery 1.8.3 jQuery Mobile 1.3.0 Beta 1 (both js and css)
Tested on platforms: HTC Evo 3D - Android 4.0.3 Droid Bionic - Android 4.0.4
Side Note: I am using Cordova to run the app. However, I did not include any Cordova javascript on the page.