This problem exists at least on NetBSD 2.0.2, perhaps older releases
are affected by this bug too.

Please, observe that the toor account (that runs a Bourne login shell
by default) is wrongly identified as Bourne-again shell (bash) based:

$ grep "/root" /etc/passwd
root:*:0:0:Charlie &:/root:/bin/csh
toor:*:0:0:Bourne-again Superuser:/root:/bin/sh

Can I suggest applying this patch on affected releases?

--------------------------------------------------------------
--- passwd	2005-09-07 21:18:03.000000000 +0200
+++ passwd.new	2005-09-07 21:18:20.000000000 +0200
@@ -1,5 +1,5 @@
 root:*:0:0:Charlie &:/root:/bin/csh
-toor:*:0:0:Bourne-again Superuser:/root:/bin/sh
+toor:*:0:0:Bourne-shell Superuser:/root:/bin/sh
 daemon:*:1:1:The devil himself:/:/sbin/nologin
 operator:*:2:5:System &:/usr/guest/operator:/bin/csh
 bin:*:3:7:Binaries Commands and Source:/:/sbin/nologin
--------------------------------------------------------------

If this change is accepted, I can open a PR to provide some
feedback on the change and why it happened.  Just to make it
"official" for people tracking source code.

Cheers,
Igor.