I am going to risk hurting some feelings here. I adore Jules. I think she is a great person, and a dedicated songstress. But her voice is challenging to mix. Sadly Jules suffers a lack of natural resonance and timber in some ranges, and it is my opinion that she tries to compensate with vibrato. The engineer has to create those harmonic overtones artificially, and flatten the vibrato. I have yet to hear her voice mixed correctly (this is not meant as an insult to you).
It needs pitch correction. It is not about being in perfect key, it needs to be pitched to match the instrumentations used (she is not doing it naturally herself and often her pitch is forcing the songs key out of range). I think the vocal track is also too dry for her voice. I might try a delay effect or some convolution verb. I also think most people are cutting to deeply into the low end of her vox. Her natural timbre is in the lower spectrum.
I am sincerley uncomfortable making these critiques, and the sad truth is it is not specifically your fault Eko. It is ours for coddling our charished songstress perhaps too much. I have held back on a half dozen recent songs with her vocals, but this time... I had to speak up.
(I am sorry Jules, please don't hate me).