[zellyx]

I believe she's a mezzo soprano with somewhere around a 2.5 octave range...
I'm a mezzo as well and my range is basically hers..

Something happened with her singing technique that altered her range - she got into some kind of bad habit, now she can't sing those higher notes like she used to. But I believe they're still in her range, albeit uncomfortably. We hear some of this in progress -- it's strained.
The high note range has to be "unlocked" again./

Because she basically never stops singing, I'm guessing any mistakes she's had haven't been fixed... they just keep snowballing!! So even after she had that vocal coach during her early era, after that, she fell into the wrong technique and it was never really fixed..