She's actually OK/passable when she sings straight, as she does on these hooks. That's fine. She can hold a tune and is generally quite consistent when well in her tessitura.
The problem is when she's constantly trying to sound like the Beyonce of fifth harmony, doing all those runs and adlibs. Her voice simply isn't remotely agile and so she forces every single run with her jaw, which also has horrible tension. Her upper belting range is also incredibly weak, especially for a lyric soprano, so it's just the perfect mixture of ingredients for a disaster. The only reason people think her voice sounds ~unique~ is because this is a girl with an overwhelmingly pop voice desperately trying to riff and run like Brandy. It's a mess.
I have no interest in whether or not she succeeds, so when she finally releases her single I just hope she doesn't feel the need to go ridiculously crazy on the runs as she does in 5H.