It works fine if you use the core module Data::Dumper for your dumping. Easiest solution?

$ perlbrew use perl-5.28.1
[download]

$ perl -ML -E 'say Data::Dumper->Dump([HTTP::Tiny->new->get("https://w
+ww.perlmonks.org")->{headers}])'

$VAR1 = {
          'etag' => '"e96f-595f85f776cd3"',
          'content-length' => '59759',
          'last-modified' => 'Mon, 28 Oct 2019 13:21:09 GMT',
          'content-type' => 'text/html',
          'date' => 'Mon, 28 Oct 2019 13:22:14 GMT',
          'server' => 'Apache/2.4.41',
          'accept-ranges' => 'bytes'
        };
[download]

$ perlbrew use perl-5.30.0
[download]

$ perl -ML -E 'say Data::Dumper->Dump([HTTP::Tiny->new->get("https://w
+ww.perlmonks.org")->{headers}])'

$VAR1 = {
          'last-modified' => 'Mon, 28 Oct 2019 13:21:09 GMT',
          'content-type' => 'text/html',
          'content-length' => '59759',
          'etag' => '"e96f-595f85f776cd3"',
          'date' => 'Mon, 28 Oct 2019 13:22:23 GMT',
          'accept-ranges' => 'bytes',
          'server' => 'Apache/2.4.41'
        };
[download]

Hope this helps!