Perhaps only the %StudentLogins or %InstructorLogins hashes have data with true values. Something like this will confirm it:

use Data::Dumper;

print Data::Dumper->Dump([\%RegStudentNew, \%RegInstructorNew,
    \%RegStudentExisting, \%RegInstructorExisting,
    \%StudentLogins, \%InstructorLogins ],
    [qw( RegStudentNew, RegInstructorNew, RegStudentExisting,
         RegInstructorExisting, StudentLogins, InstructorLogins )]);
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