I can't reproduce your problem:

#!/usr/bin/perl
use strict;
use warnings;

$ENV{CLEARCASE_VIEW_TAG} = 'result';

if ("i can haz result" =~ $ENV{CLEARCASE_VIEW_TAG}) {
    print "match\n";
}
__END__
match
[download]

So chances are that one of the variables doesn't contain what you think it does. Try to use Data::Dumper to find out. Be sure to set $Data::Dumper::Useqq = 1 before using it, that way non-printable characters will also be shown.