sam3 selects only white for zebra crossings

How do I select only the white portion of a zebra crossing using SAM3? My prompt says "zebra crossing". Could you please take a look and see if there's a problem? I was planning to use SAM3 to generate some data.

Start by reproducing the reported SAM3 result with the "zebra crossing" prompt and the attached examples. Compare the selected mask with the expected white crossing area, then inspect the inference and prompting path to determine whether this is expected model behavior or a defect. Done means the behavior is explained or a narrowly scoped fix is identified and verified.

Written by the indexing model from the issue text.