Maybe the theatrical T2-3D experience is using a newly teal'd DCP these days. :P
2012 HD cam
1996 cam pro-shot via the Making Of doc (Unfinished version? The background is plain.)
The design photos by the animation director indicate that this scene was conceived as blue.
Also these two, 2012 cam vs. actual film transfer:
http://s21.postimg.org/5b1xdy0br/T2_3_D_2012_HD_cam_2.jpg
http://s21.postimg.org/ph5fctvzb/T2_3_D_Making_Of_film_clip.jpg