Deparsed output:

perl -MO=Deparse -MData::Dumper -le '%h = (1 => 2, a=>"b", c => 2); %h
+ = reverse ( %x = reverse %h); print Dumper({x => \%x, h =>\%h});'
BEGIN { $/ = "\n"; $\ = "\n"; }
use Data::Dumper;
(%h) = (1, 2, 'a', 'b', 'c', 2);
(%h) = reverse((%x) = reverse(%h));
print Dumper({'x', \%x, 'h', \%h});
-e syntax OK
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as stated above your reverse/reverse of the hash is causing you to lose dup keys...