why resize image and 2d bbox labels only?

[FlyingAnt2018]

TransFusion/mmdet3d/datasets/pipelines/loading.py

Line 223 in 73c596f

for key in results.get('bbox_fields', []):

HI, I am doing same research on mono 3d object detection, and i wonder why do you only resize image and 2d bbox only, and do not resize gt_bboxes_3d ? For the regression procedure is regressing direct to gt_bboxes_3d not gt_bboxes(2d box annotations).
i follow mmdetection official "Resize" augmentation to get error result, as figure below.

I am looking forward to a reply;