pack('C'...) sets UTF8 flag

Am I doing something wrong or is this a bug:

use strict;
my $p;
foreach $p (qw (C U C))
{
   my $s = pack($p, 200);
   print "pack('$p', 200): is_utf8=" . (utf8::is_utf8($s) ? 'yes' : 'no ') 
. "\t$s\t" . join(',', unpack('C*', $s)) . "\n";
}

Generates the following output:

pack('C', 200): is_utf8=no      ╚       200
pack('U', 200): is_utf8=yes     ╚       195,136
Wide character in print at T:\test2.pl line 8.
pack('C', 200): is_utf8=yes     ╚       200

Specifically, the first and last ought to be the same, and I shouldn't be 
getting that error.

Seen on perl 5.8.3, 5.8.6 and 5.8.7. E.g., my current perl -v:
This is perl, v5.8.7 built for MSWin32-x86-multi-thread
(with 7 registered patches, see perl -V for more detail)

Copyright 1987-2005, Larry Wall

Binary build 813 [148120] provided by ActiveState 
http://www.ActiveState.com
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Built Jun  6 2005 13:36:37

TIA,

Bob