500 Fatal Error when making API call

I just upgrade WordPress and WooCommerce to the latest versions and my API calls are failing with a 500 error. Error log output below.

Any help or guidance would be appriciated.

Uncaught WC_Data_Exception: Invalid discount type in /code/wp-content/plugins/woocommerce/includes/abstracts/abstract-wc-data.php:943 Stack trace: #0 /code/wp-content/plugins/woocommerce/includes/class-wc-coupon.php(549): WC_Data->error(‘coupon_invalid_…’, ‘Invalid discoun…’) #1 /code/wp-content/plugins/woocommerce/includes/class-wc-coupon.php(1188): WC_Coupon->set_discount_type(‘adp_fixed_cart_…’) #2 /code/wp-content/plugins/woocommerce/includes/rest-api/Controllers/Version2/class-wc-rest-orders-v2-controller.php(297): WC_Coupon->set_short_info(Array) #3 [internal function]: WC_REST_Orders_V2_Controller->get_order_item_data(Object(WC_Order_Item_Coupon)) #4 /code/wp-content/plugins/woocommerce/includes/rest-api/Controllers/Version2/class-wc-rest-orders-v2-controller.php(475): array_map(Array, Array) #5 /code/wp-content/plugins/woocommerce/includes/rest-api/Controllers/Version2/class-wc-rest-orders-v2-controller.php(543): WC_REST_Orders_V2_Controller->get_formatted_item_data(Object(Automattic\WooCommerce\Admin\Overrides\Order)) #6 /code/wp-content/plugins/woocommerce/includes/rest-api/Controllers/Version3/class-wc-rest-crud-controller.php(391): WC_REST_Orders_V2_Controller->prepare_object_for_response(Object(Automattic\WooCommerce\Admin\Overrides\Order), Object(WP_REST_Request)) #7 /code/wp-includes/rest-api/class-wp-rest-server.php(1230): WC_REST_CRUD_Controller->get_items(Object(WP_REST_Request)) #8 /code/wp-includes/rest-api/class-wp-rest-server.php(1063): WP_REST_Server->respond_to_request(Object(WP_REST_Request), ‘/wc/v2/orders’, Array, NULL) #9 /code/wp-includes/rest-api/class-wp-rest-server.php(439): WP_REST_Server->dispatch(Object(WP_REST_Request)) #10 /code/wp-includes/rest-api.php(428): WP_REST_Server->serve_request(‘/wc/v2/orders’) #11 /code/wp-includes/class-wp-hook.php(324): rest_api_loaded(Object(WP)) #12 /code/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters(NULL, Array) #13 /code/wp-includes/plugin.php(565): WP_Hook->do_action(Array) #14 /code/wp-includes/class-wp.php(418): do_action_ref_array(‘parse_request’, Array) #15 /code/wp-includes/class-wp.php(813): WP->parse_request(”) #16 /code/wp-includes/functions.php(1336): WP->main(”) #17 /code/wp-blog-header.php(16): wp() #18 /code/index.php(17): require(‘/code/wp-blog-h…’) #19 {main} thrown in /code/wp-content/plugins/woocommerce/includes/abstracts/abstract-wc-data.php on line 943 CONTEXT: {“data”:null}