Perl ternary errantly enters "else" clause?

I have the following code:

# List of tests
my $tests = [("system_test_builtins_sin", "system_test_builtins_cos", "system_test_builtins_tan")];

# Provide overrides for certain variables that may be needed because of special cases
# For example, cos must be executed 100 times and sin only 5 times.
my %testOverrides = (
    system_test_builtins_sin => {
        reps => 5,
    },
    system_test_builtins_cos => {
        reps => 100,
    },
);

my %testDefaults = (
    system_test_reps => 10,
);

# Execute a system tests
foreach my $testName (@$tests)
{
    print "Executing $testName\n";
    my $reps;

    if (exists $testOverrides{$testName}{reps})
        { $reps = $testOverrides{$testName}{reps}; }
    else
        { $reps = $testDefaults{system_test_reps}; }
    print "After long if: $reps\n";
    exists $testOverrides{$testName}{reps} ? $reps = $testOverrides{$testName}{reps} : $reps = $testDefaults{system_test_reps};
    print "After first ternary: $reps\n";
    exists $testOverrides{$testName}{reps} ? $reps = $testOverrides{$testName}{reps} : print "Override not found.\n";
    print "After second ternary: $reps\n";
}

This gives the following output:

Executing system_test_builtins_sin
After long if: 5
After first ternary: 10
After second ternary: 5
Executing system_test_builtins_cos
After long if: 100
After first ternary: 10
After second ternary: 100
Executing system_test_builtins_tan
After long if: 10
After first ternary: 10
Override not found.
After second ternary: 10

This output is most unexpected! I don't understand why the first ternary seems to always be executing the "if false" clause. It is always assigning a value of 10. I also tried changing the "false" clause to $reps = 6, and I saw that it always got the value of 6. Why does the ternary's logic depend on the content of the third (if false) clause?