get_batch() returns mmco: unref short failure, even for a valid frame

get_batch returns " [h264 @ 0x561c38325ac0] mmco: unref short failure ", for some frames in the middle of the video. Video plays fine and there is no other issue.

To recreate the problem for one of the many videos do the following:
1) download this https://www.rocq.inria.fr/cluster-willow/amiech/Youcook2_val.zip
2) extract and download Youcook2_val/validation/201/mZwK0TBI1iY.mkv
3) Load the video using vr=VideoReader(..)
4) Do a vr.get_batch([257]).shape
5) Although it has 7939 frames, it throws error while getting frame 257.

Could you please help me debug this?

Thanks