Duplicated keys in when using doted keys

[chadidi]

{"test": {"one": "now", "two": true,}, "testflat": "flat", "test.one": "now", "test.two": true}

This is stored in my database when using setMultiple and also retrieved in the same way.

my default settings:

public $defaultSettings = [
    'testflat' => 'flat',
    'test.one' => 'now', 
    'test.two' => true,
];