cookies - php setcookie specific expire date not working

one text

I am trying to set a cookie with a specific expiry date using ....

$result=setcookie("testA", "A", strtotime("2038-01-01 23:59:59"));

but this is returning [$result=] true, but the expiry date is 2023-12-08.

To test this further I've run the following PHP, and find that the dates become static after test14.

$chk=2147483647;
$monthNb = 30 * 24 * 60 * 60;

for($n=0; $n<40; $n++) {

   $nn=$n;
   if ( $n<10 ) $nn="0$nn";

   $v=$n*$monthNb;
   if ( $v>$chk ) echo "<LI>ERR $v";
   setcookie("test$nn", "$v", time() + $v);
}

Resulting in...