{
  "astropy__astropy-12907": {
    "model_name_or_path": "openai/qwen36-27b",
    "instance_id": "astropy__astropy-12907",
    "model_patch": "diff --git a/astropy/modeling/separable.py b/astropy/modeling/separable.py\nindex a308e2729..45bea3608 100644\n--- a/astropy/modeling/separable.py\n+++ b/astropy/modeling/separable.py\n@@ -242,7 +242,7 @@ def _cstack(left, right):\n         cright = _coord_matrix(right, 'right', noutp)\n     else:\n         cright = np.zeros((noutp, right.shape[1]))\n-        cright[-right.shape[0]:, -right.shape[1]:] = 1\n+        cright[-right.shape[0]:, -right.shape[1]:] = right\n \n     return np.hstack([cleft, cright])\n \n"
  }
}