Object is the base class of basically all of our QML types - Object QML Type | ArcGIS for Developers
Object has an errorChanged signal. I recommend you hook up to this signal on your various classes (the sync task objects, for example), and see if you can get anything useful out of it:
onErrorChanged: {
if (error)
console.log("Error:", error.message, error.additionalMessage);
}
One wild guess would be that something relies (via property binding perhaps?) on the spatial reference of the map/basemap, and not having a basemap is messing that up somehow. Just a guess, but hopefully there is some sort of useful error message coming back to help us further narrow down the issue.
