The eq operator is not an indicator. See Devel::Peek.

    > cat 1.pl
    use Test::More tests => 1;
    
    use JSON::XS qw( decode_json encode_json );
    
    my $s_orig = "\xE2\x98\xBB";
    
    my $data_orig = [ $s_orig ];
    my $json_utf8 = encode_json($data_orig);
    my $data_got = decode_json($json_utf8);
    my $s_got = $data_got->[0];
    is($s_got, $s_orig);
    
    use Devel::Peek;
    
    print "orig $s_orig\n";
    Dump $s_orig;
    
    print "\ngot $s_got\n";
    Dump $s_got;
    
    
    > perl 1.pl
    1..1
    ok 1
    orig ☻
    SV = PV(0x9b946c8) at 0x9badb40
      REFCNT = 1
      FLAGS = (PADMY,POK,IsCOW,pPOK)
      PV = 0x9bb2808 "\342\230\273"\0
      CUR = 3
      LEN = 10
      COW_REFCNT = 2
    
    got ☻
    SV = PV(0x9b94798) at 0x9ea91dc
      REFCNT = 1
      FLAGS = (PADMY,POK,IsCOW,pPOK,UTF8)
      PV = 0x9bb7c10 "\303\242\302\230\302\273"\0 [UTF8 "\x{e2}\x{98}\
+x{bb}"]
      CUR = 6
      LEN = 10
      COW_REFCNT = 1
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