It works for me. Show your code, please. Mine is the following:

{
   open(my $fh, '>:raw', 'file') or die("open>: $!\n");
   print $fh ("abc\x{0D}\x{0A}de\x{0A}fg\x{0D}\x{0A}");
   #           [------5------][---------7----------]
   #           [------5------][---3--][------4-----]
}

{
   open(my $fh, '<:raw', 'file') or die("open<: $!\n");
   local $/ = "\x0D\x0A";
   print length, "\n" while <$fh>;
}
[download]

outputs

5
7
[download]

If you remove the assignment to $/, the output is

5
3
4
[download]