You only showed how you opened the file. You haven't shown how you read the file and how you verify what was read.

The following works for me:

#! /usr/bin/perl
use warnings;
use strict;

while (<DATA>) {
    print;
}

__DATA__
<perl programming1234>
"23rd June 2016"
#Thursday, 11:05am#
<perl programming5678> problem encountered
[download]

Maybe you checked the output in a browser? You need to inspect the page source to see the tag-like strings, or wrap the whole output in <pre> tags.

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,
[download]