Cannot use object of type stdClass as array

[iNDicat0r]

I get the following error in my slim3 app:

Cannot use object of type stdClass as array

Message: Cannot use object of type stdClass as array
File: /var/www/slimapi/vendor/bshaffer/oauth2-server-php/src/OAuth2/Controller/ResourceController.php
Line: 83

basically mongodb return data of type stdClass and the library tries to access the data in the array fashion and therefore it throws the error.

I am using the following options for the mongoDB/Client driver options:
$driver_options['typeMap'] = ['array' => 'array', 'document' => 'array'];

Any idea what is wrong ?