Did you forgot to remove the parens? You should have gotten a warning and a strict error, but of which explain the issue.

use strict;
use warnings;

my @perls = (1, 2, 3, 4);
sub foo
{
  my @foo = @{shift};
  return join $/, @foo
}
print foo(\@perls)
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Ambiguous use of @{shift} resolved to @shift at a.pl line 7.
Global symbol "@shift" requires explicit package name at a.pl line 7.
Execution of a.pl aborted due to compilation errors.
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