I am not experiencing that :(. Consider this code example:

# encrypts password using
# SHA-1 algorithm
my $sha1 = Digest::SHA1->new;

# reset algorithm
$sha1->hexdigest;

# encrypt
$salt = 1658087940;
my $secret = $sha1->sha1_hex($passwd . $salt);
[download]

Run in a shell script the hash is the same each time the salt and password are the same (as you said). However, when inserted into a web page (HTML::Mason but, on the same machine) the hash is different each time.