Please note that there is a workaround for this issue, if you add the cordova JS file manually to the index.html file :
This is in addition to including the file in the app.json file:
<!-- The line below must be kept intact for Sencha Command to build your application -->
Please also note, that adding the cordova JS file manually to the production index.html also works ( after the 'sencha app build production' command). Therefore, (and I assume that with a very modest knowledge regarding the Sencha Touch Core ) the problem is probably with the process of automatically loading the script. This assumption is particularly weird for me, because the jquery's JS file loads normally.
"bundle": true, /* Indicates that all class dependencies are concatenated into this file when build */
I hope that this may help locating the root cause of this issue.