I have done a bit fault finding and want to share my results with you.
First, the issue you mentioned in which two lines were calling the same script did not apply in my case. So I looked further.
When I connect an iPad 2 or iPad 3 (=iOS 9) the page does not load properly. The behaviour is independent of whether I am running Safari, Edge, iCab or Firefox. I see only the view as above (which is the same view that one gets when index.html is loaded without the web server running). So my guess was that processing the code of the page did not complete properly.
I hooked the old iPad via "Developer Options" to desktop Safari and looked at the debugger.
With iOS9 I get an error in ../www/_configurations/additional.js, line 8: Unexpected Identifier aModules.
If I watch the expression "aModules", it says aModules: [Exception: ReferenceError: Can't find variable: aModules]
With actual iOS 12 I don't get this error message, the page loads perfectly. The value is then aModules=.
So it is somehow client-dependent.
From the comment "...is automatically generated..." in file "additional.js" I concluded by means of a full text search that the file additional.js is generated by the source text file SettingsUtils.java.
As the folder ../www/_configurations with all files inside (among them additional.js) is created on every server start, I cirumvented this problem temporarily by overwriting the freshly generated additional.js with a backup version that comments out most of the code (=all between line 8 and 24) and which adds the desired result aWorkingModules=; before the last line angular.resumeBootstrap(aWorkingModules); is called. Of course this procedure will not allow me to include my own scripts later, but I can at least use an iPad 2 to display the GUI for the time being.
To me it looks as if older iOS cannot properly deal with the variable aModules. Newer versions seem to assume an empty string, while older iOS versions throw an error, which prevents the page from loading correctly.
I kindly ask whether there is a way to prevent this error from occurring in later versions of MyController.
Kind regards, Matt.