That snippet is perfectly fine. Your problem is somewhere else. Please post code that reproduces the problem. Something other than the following:

#!/usr/bin/perl -w
use strict;

test( FLOATER => 'N');

sub test {
    my %data = @_;
    warn $data{'FLOATER'};
    print $data{'FLOATER'}."<-----------";
    if( $data{'FLOATER'} eq 'Y' ){
        print "Test: yes\n";
    }
}
__OUTPUT__
N at test.pl line 8.
N<-----------
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