Questions regarding 3D lifting from 2D joints (posenet)

[basicvisual]

Hello ,
I could manage to port the 2D joint detection from posenet to Arash Hosseinis 3d.pose-baseline .
However , i notice that , on doing the 3D lifting , the 3d skeleton seems to be flipped in the axes. I was wondering what could be the reason ?
Example :
https://drive.google.com/file/d/1SaaJJ08rG8CqbmJcMCXXB49oYzs7nH0G/view?usp=sharing
Could it be that the camera mapping from 2d to 3d ? Have you seen such issue before ? Tips are appreciated.