I cannot figure out the following seemingly trivial regex, so I hope some wisdom can be dispensed...

I have a 4-char string, consisting of 'abc' plus a closing newline.
When matching until the end of the string, I get a different result when using '.*$' vs '.*?$': in the first case the closing newline is included, in the second, it is not. Note that /s is being used.
I am mystified how the end of the string can be interpreted different in these regexes, but apparently it is.
What am I missing here?
When the closing char is not a newline, the results are identical, as expected.
This in in Perl v5.14.4 (no options to use a different version).

Thanks much in advance for guidance!

$s = "abc\n";
if ($s =~ /(ab.*?)$/s) {
    $p = substr($s, @-[1], (@+[1] - @-[1]));
    print("match A=[$p] length=".length($p)."\n");
}
if ($s =~ /(ab.*)$/s) {
    $q = substr($s, @-[1], (@+[1] - @-[1]));
    print("match B=[$q] length=".length($q)."\n");
}

result:

match A=[abc] length=3
match B=[abc
] length=4
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