Unfortunately, it would be very hard to identify the main cause for this behavior without a glimpse on the used code and optionally some details about the device and the AppBuilder client used.
A wild guess would be that the emulatorMode
flag was set to true when deploying to a device (or somehow was saved to the device through the LiveSync option).
Could you please verify for any differences between the working and the not working versions?
Just a quick note: the repository you have cloned is the parent source and is also working. There are minor UI differences and such in the namings of the variables.
Please, let us know if you have questions.