This is in the fatal error log.
2023-04-12T11:00:00+00:00 CRITICAL Uncaught Error: Attempt to assign property "Subscriber ID" on int in [REMOVED]/wp-content/plugins/yith-woocommerce-subscription/plugin-fw/yit-woocommerce-compatibility.php:112
Stack trace:
#0 [REMOVED]/wp-content/plugins/yith-woocommerce-subscription/plugin-fw/yit-woocommerce-compatibility.php(140): yit_set_prop(5565, Array, 'I-NCH8CN5D0JNC')
#1 [REMOVED]/wp-content/plugins/yith-woocommerce-subscription/includes/gateways/paypal/includes/class.ywsbs-paypal-ipn-handler.php(333): yit_save_prop(5565, Array, false, true)
#2 [REMOVED]/wp-content/plugins/yith-woocommerce-subscription/includes/gateways/paypal/includes/class.ywsbs-paypal-ipn-handler.php(157): YWSBS_PayPal_IPN_Handler->paypal_ipn_request(Array)
#3 [REMOVED]/wp-content/plugins/yith-woocommerce-subscription/includes/gateways/paypal/includes/class.ywsbs-paypal-ipn-handler.php(80): YWSBS_PayPal_IPN_Handler->process_paypal_request(Object(Automattic\WooCommerce\Admin\Overrides\Order), Array)
#4 [REMOVED]/wp-includes/class-wp-hook.php(308): YWSBS_PayPal_IPN_Handler->valid_response(Array)
#5 [REMOVED]/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters('', Array)
#6 [REMOVED]/wp-includes/plugin.php(517): WP_Hook->do_action(Array)
#7 [REMOVED]/wp-content/plugins/woocommerce/includes/gateways/paypal/includes/class-wc-gateway-paypal-ipn-handler.php(49): do_action('valid-paypal-st...', Array)
#8 [REMOVED]/wp-includes/class-wp-hook.php(308): WC_Gateway_Paypal_IPN_Handler->check_response('')
#9 [REMOVED]/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters('', Array)
#10 [REMOVED]/wp-includes/plugin.php(517): WP_Hook->do_action(Array)
#11 [REMOVED]/wp-content/plugins/woocommerce/includes/class-wc-api.php(161): do_action('woocommerce_api...')
#12 [REMOVED]/wp-includes/class-wp-hook.php(308): WC_API->handle_api_requests(Object(WP))
#13 [REMOVED]/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters(NULL, Array)
#14 [REMOVED]/wp-includes/plugin.php(565): WP_Hook->do_action(Array)
#15 [REMOVED]/wp-includes/class-wp.php(399): do_action_ref_array('parse_request', Array)
#16 [REMOVED]/wp-includes/class-wp.php(780): WP->parse_request('')
#17 [REMOVED]/wp-includes/functions.php(1332): WP->main('')
#18 [REMOVED]/wp-blog-header.php(16): wp()
#19 [REMOVED]/index.php(17): require('/nas/content/li...')
#20 {main}
thrown in [REMOVED]/wp-content/plugins/yith-woocommerce-subscription/plugin-fw/yit-woocommerce-compatibility.php on line 112
There is a corresponding Paypal log that is too big to post here, but below is the end of it.
2023-04-12T11:02:02+00:00 INFO Received valid response from PayPal IPN
2023-04-12T11:02:02+00:00 INFO YWSBS - Found order #2405
2023-04-12T11:02:02+00:00 INFO YWSBS - Txn Type: subscr_payment
2023-04-12T11:02:02+00:00 INFO YWSBS - Validate currency OK
2023-04-12T11:02:02+00:00 INFO YWSBS - Receiver Email OK
2023-04-12T11:02:02+00:00 INFO YSBS - Paypal IPN Request Start
2023-04-12T11:02:02+00:00 INFO YSBS - Transaction ID already processed
2023-04-12T11:02:02+00:00 INFO Found order #2405
2023-04-12T11:02:02+00:00 INFO Payment status: completed
2023-04-12T11:02:02+00:00 INFO Aborting, Order #2405 is already complete.