Error: Illegal offset type in isset or empty in /mysite/wp-includes/taxonomy.php

$terms = wp_get_post_terms( 637, ‘post_tag’, array( ” ) );
var_dump( $terms );

Throws the following error:

PHP Warning: Illegal offset type in isset or empty in /mysite/wp-includes/taxonomy.php on line 290

#0 /mysite/wp-includes/taxonomy.php(290): WPConsole\Core\Console\Psy\Shell->handleError(2, ‘Illegal offset …’, ‘/home/myultrawe…’, 290, Array)
#1 /mysite/wp-includes/taxonomy.php(311): taxonomy_exists(Array)
#2 /mysite/wp-content/plugins/real-category-library/inc/general/TaxOrder.class.php(84): is_taxonomy_hierarchical(Array)
#3 /mysite/wp-includes/class-wp-hook.php(289): RCL_TaxOrder->get_terms_orderby(‘t.name’, Array)
#4 /mysite/wp-includes/plugin.php(206): WP_Hook->apply_filters(‘t.name’, Array)
#5 /mysite/wp-includes/class-wp-term-query.php(891): apply_filters(‘get_terms_order…’, ‘t.name’, Array, Array)
#6 /mysite/wp-includes/class-wp-term-query.php(399): WP_Term_Query->parse_orderby(‘name’)
#7 /mysite/wp-includes/class-wp-term-query.php(288): WP_Term_Query->get_terms()
#8 /mysite/wp-includes/taxonomy.php(1182): WP_Term_Query->query(Array)
#9 /mysite/wp-includes/taxonomy.php(2031): get_terms(Array)
#10 /mysite/wp-includes/post.php(3448): wp_get_object_terms(Array, Array, Array)
#11 /mysite/wp-content/plugins/wp-console/includes/Core/Console/RestController.php(137) : eval()’d code(1): wp_get_post_terms(637, ‘post_tag’, Array)
#12 /mysite/wp-content/plugins/wp-console/includes/Core/Console/RestController.php(137): eval()
#13 /mysite/wp-includes/rest-api/class-wp-rest-server.php(1015): WPConsole\Core\Console\RestController->create_item(Object(WP_REST_Request))
#14 /mysite/wp-includes/rest-api/class-wp-rest-server.php(342): WP_REST_Server->dispatch(Object(WP_REST_Request))
#15 /mysite/wp-includes/rest-api.php(306): WP_REST_Server->serve_request(‘/wp-console/v1/…’)
#16 /mysite/wp-includes/class-wp-hook.php(287): rest_api_loaded(Object(WP))
#17 /mysite/wp-includes/class-wp-hook.php(311): WP_Hook->apply_filters(NULL, Array)
#18 /mysite/wp-includes/plugin.php(544): WP_Hook->do_action(Array)
#19 /mysite/wp-includes/class-wp.php(388): do_action_ref_array(‘parse_request’, Array)
#20 /mysite/wp-includes/class-wp.php(735): WP->parse_request(”)
#21 /mysite/wp-includes/functions.php(1274): WP->main(”)
#22 /mysite/wp-blog-header.php(16): wp()
#23 /mysite/index.php(17): require(‘/home/myultrawe…’)