Using `set_cwd` breaks the consistency of re-running parts of a Lean file

In an editor, put the following in a Lean file:

def bar := ()

run_cmd
   unsafe_run_io $ do
   { io.env.get_cwd >>= io.print_ln,
     io.env.set_cwd "foo",
     io.env.get_cwd >>= io.print_ln }

/some/path/
/some/path/foo/

without restarting the Lean server, comment out the bar definition:

-- def bar := ()

run_cmd
   unsafe_run_io $ do
   { io.env.get_cwd >>= io.print_ln,
     io.env.set_cwd "foo",
     io.env.get_cwd >>= io.print_ln }

/some/path/foo/
/some/path/foo/foo/

Reproduce the issue in a Lean file using the shown run_cmd and unsafe_run_io sequence, first with and then without the bar definition. Start by tracing how the editor reruns parts of the file and how the Lean server handles io.env.get_cwd and io.env.set_cwd. Done means rerunning the remaining command does not inherit the prior working-directory change.