A semicolon is missing after use Pod::Simple::HTML.
I also get this warning when running your (fixed) code:

Malformed UTF-8 character (unexpected continuation byte 0xbe, with no 
+preceding start byte) at 911435.perl line 10.
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Update: This warning remains even if I only keep this:

#!/usr/bin/perl
use strict;
use warnings;
use utf8;
my $content = <<CONTENT;
=head1 foobar

L<<utf-8 letter (a with ogonek) which i can't paste here because perlm
+onks doesn't support unicode>>>

=cut
CONTENT
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