Alternatively, remove the space afterwards. 
sub trim {
   for (my $s = $_[0]) {
      s/^\s+//;
      s/\s+$//;
      return $_;
   }
}

$string =~ s/##([^#]+)##/##$langhash{trim($1)}##/;

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In reply to Re: substitution not working correctly by ikegami
in thread substitution not working correctly by qnguyen

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