In git main it appears to work but with a warning:
$ guile --r7rs
GNU Guile 3.0.7.13-c1fd55-dirty
...
scheme@(guile-user)> (import (scheme base))
scheme@(guile-user)> (member 'a '(b))
WARNING: (guile-user): imported module (scheme base) overrides core binding `member'
$1 = #f
scheme@(guile-user)> (member 'a '(b a))
$2 = (a)
-Dale
-----------------------------------------
From: "Arvydas Silanskas"
To: 48765@debbugs.gnu.org
Cc:
Sent: Monday May 31 2021 5:10:12PM
Subject: bug#48765: `member` from (scheme base) returns empty list instead of #f when item is not found
Default `member` works fine:
$ guile
> (member 'a '(b)) $1 = #f
However, using scheme base it returns empty list
$ guile --r7rs
> (import (scheme base))
> (member 'a '(b))
$1 = ()
Other functions (memq, memv) seem to work fine.
I am using version 3.0.5 as distributed by debian bullseye