Why SAM not able draw polygon in less thickness line area

I am trying to separate polygon, as you can see in the images few are not able to predict as expected. I have tried changing parameter by checking pred_iou_thresh and stability_score_thresh in SamAutomaticMaskGenerator. especially in the greenery area missing of the polygons.

Start with the SamAutomaticMaskGenerator entry point and the reported pred_iou_thresh and stability_score_thresh parameters. Reproduce the behavior with the linked image, focusing on missing polygons in greenery and thin-line areas, then document whether the issue is caused by threshold settings or another limitation.

Written by the indexing model from the issue text.