for those asking if shield can side load starhub go on it ... the answer is no .. the app will kick out ... but works for VIU .. Singtel Cast and TVB anywhere
I can only guess StarHub has two versions of StarHub Go app, one for normal mobile version of Android OS and one for the Android TV OS (StarHub Go Streaming Box runs service provider version of Android TV).
The Android TV version is probably tied to the Go Streaming Box and it probably checks the underlying OS is Android TV. If not it will quit. If yes it is running Android TV, it will check if it is the StarHub Box, if not it will quit.
The mobile version you are trying to sideload will probably do the same thing, if the os is mobile version of Android, it will proceed. If the underlying OS is Android TV, it will quit.
Just my guess.