Strange result for Jordan_form()

edit

     M = matrix([[4,-1,6],[2,1,6],[2,-1,8]])
    MM=M.jordan_form(transformation=true)
    show(MM)
    show(MM[0])
    show(MM[1])
    show(MM[1]^(-1))
    show(MM[1]^(-1)*MM[1])
    show(MM[1]^(-1)*MM[0]*MM[1])
    show(bool(MM[1]^(-1)*MM[0]*MM[1]==M))

According to the documentation and what I know of Jordan decomposition the last line should be True. No ?