Redundant boxes after post processing

[zhaowenZhou]

It seems like the configuration: "use_rotate_nms = False, use_multi_class_nms = True" cannot remove all redundant boxes and there are still lots of boxes at the same position. Is this normal?
Also, though I set score_threshold = 0.1 in test_cfg, there are lots of boxes with score less than 0.1 in the final output