You copied everything out of the tied hash %temp into the non-tied hash %hash and then tested that. Here is a version of your code that demonstrated that it is still tied:

use Tie::IxHash;
use strict;
use warnings;

{
   my %hash;
   print ref(tie(%hash, "Tie::IxHash"))."\n";
   $hash{'hi'} = 1;
   $hash{'there'} = 2;
   some(\%hash);
}

sub some{
   my $temp = shift;
   print ref($temp)."\n";
   # my %hash = %{$temp};
   # print ref(tied(%hash));
   print ref(tied(%{$temp}));
}
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