Steps To Reproduce

from sage.all import *

M = Matrix(GF(2), [[1,1],[0,1]])
basis = [vector(GF(2), [0,1])]
vector_space = span(basis)
image_basis = [M * b for b in vector_space.basis()]
image = span(image_basis)
print(image.basis())
print(image_basis, image_basis[0] in image, image_basis[0] in image.basis())

Expected Behavior

[
(1, 1)
]
[(1, 1)] True True

Actual Behavior

[
(0, 1)
]
[(1, 1)] True False

Additional Information

Replacing the line image_basis = [M * b for b in vector_space.basis()] with image_basis = [M * b for b in basis] yields the correct result.

Environment

• OS: Ubuntu 24.04.2 LTS
• Sage Version: 10.6 (installed from conda-forge)
• Python Version: 3.12.8

Checklist

• I have searched the existing issues for a bug report that matches the one I want to file, without success.
• I have read the documentation and troubleshoot guide