Hi Robert,
This scenario isn't expected with Cordova apps, since installing an update deletes the old files and installs completely new ones. We have not received other reports like this one, so we would need more information to be able to guess what is causing the problem. Could you confirm that this happens on both Android and WP devices? Do you notice any pattern in the devices make and model or OS versions? Also, do you distribute these apps in the public stores and do you by any chance reference any scripts/styles from a CDN instead of using local ones?
Regards,
Tsvetina
Telerik