BUG in encoding package requires spaces around « and »

A bug in the 'encoding' module seems to require spaces around the right
and left double-angle-brackets. This only is needed when a variable is
being interpolated within a double-quoted string. Here's a demonstration
program:

#!/usr/bin/perl
use strict;
use warnings;
use encoding 'iso-8859-1';

print "«Hi there»\n";
print "«Hello there again»\n";

our $string = 'Something fun';

print "«$string»"; # BUG prevents compilation
print "« $string »"; # spaces are needed around string to compile

__END__

This prints (i18n-file.pl is the name of my script):

Global symbol "%_END__" requires explicit package name at ./i18n-file.pl
line 11.
Execution of ./i18n-file.pl aborted due to compilation errors.

shell returned 255

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Comment out the first print «$string», and everything works.