AnomalousMonk has nailed the issue. Strictures (use strict; use warnings;) would have given you early warning that things were going wrong. Consider:

use strict;
use warnings;

my $dwarfs = [ qw(Doc Grumpy Happy Sleepy Sneezy Dopey Bashful) ];

print "@{$dwarfs}\n";
print "@dwarfs\n";
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Prints:

Possible unintended interpolation of @dwarfs in string at ... line 7.
Global symbol "@dwarfs" requires explicit package name at ... line 7.
Execution of ... aborted due to compilation errors.
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which should give you pause to wonder what the heck that means.