diff --git a/modules/ppcp-compat/src/PPEC/PPECHelper.php b/modules/ppcp-compat/src/PPEC/PPECHelper.php
index 71e16e544..70e882457 100644
--- a/modules/ppcp-compat/src/PPEC/PPECHelper.php
+++ b/modules/ppcp-compat/src/PPEC/PPECHelper.php
@@ -67,8 +67,12 @@ class PPECHelper {
 	 * @return bool
 	 */
 	public static function site_has_ppec_subscriptions() {
-		global $wpdb;
+		$has_ppec_subscriptions = get_transient( 'ppcp_has_ppec_subscriptions' );
+		if ( $has_ppec_subscriptions !== false ) {
+			return $has_ppec_subscriptions === 'true';
+		}
 
+		global $wpdb;
 		$result = $wpdb->get_var(
 			$wpdb->prepare(
 				"SELECT 1 FROM {$wpdb->posts} p JOIN {$wpdb->postmeta} pm ON pm.post_id = p.ID
@@ -80,6 +84,12 @@ class PPECHelper {
 			)
 		);
 
+		set_transient(
+			'ppcp_has_ppec_subscriptions',
+			! empty( $result ) ? 'true' : 'false',
+			3 * MONTH_IN_SECONDS
+		);
+
 		return ! empty( $result );
 	}
 
@@ -92,7 +102,9 @@ class PPECHelper {
 		/**
 		 * The filter returning whether the compatibility layer for PPEC Subscriptions should be initialized.
 		 */
-		return ( ! self::is_gateway_available() ) && self::site_has_ppec_subscriptions() && apply_filters( 'woocommerce_paypal_payments_process_legacy_subscriptions', true );
+		return ( ! self::is_gateway_available() )
+			&& self::site_has_ppec_subscriptions()
+			&& apply_filters( 'woocommerce_paypal_payments_process_legacy_subscriptions', true );
 	}
 
 }
diff --git a/modules/ppcp-webhooks/src/IncomingWebhookEndpoint.php b/modules/ppcp-webhooks/src/IncomingWebhookEndpoint.php
index 4a7631572..b228139e0 100644
--- a/modules/ppcp-webhooks/src/IncomingWebhookEndpoint.php
+++ b/modules/ppcp-webhooks/src/IncomingWebhookEndpoint.php
@@ -83,6 +83,14 @@ class IncomingWebhookEndpoint {
 	 */
 	private $last_webhook_event_storage;
 
+	/**
+	 * Cached webhook verification results
+	 * to avoid repeating requests when permission_callback is called multiple times.
+	 *
+	 * @var array<string, bool>
+	 */
+	private $verification_results = array();
+
 	/**
 	 * IncomingWebhookEndpoint constructor.
 	 *
@@ -160,7 +168,17 @@ class IncomingWebhookEndpoint {
 
 		try {
 			$event = $this->event_from_request( $request );
+		} catch ( RuntimeException $exception ) {
+			$this->logger->error( 'Webhook parsing failed: ' . $exception->getMessage() );
+			return false;
+		}
 
+		$cache_key = $event->id();
+		if ( isset( $this->verification_results[ $cache_key ] ) ) {
+			return $this->verification_results[ $cache_key ];
+		}
+
+		try {
 			if ( $this->simulation->is_simulation_event( $event ) ) {
 				return true;
 			}
@@ -169,9 +187,11 @@ class IncomingWebhookEndpoint {
 			if ( ! $result ) {
 				$this->logger->error( 'Webhook verification failed.' );
 			}
+			$this->verification_results[ $cache_key ] = $result;
 			return $result;
 		} catch ( RuntimeException $exception ) {
 			$this->logger->error( 'Webhook verification failed: ' . $exception->getMessage() );
+			$this->verification_results[ $cache_key ] = false;
 			return false;
 		}
 	}
diff --git a/tests/PHPUnit/TestCase.php b/tests/PHPUnit/TestCase.php
index 1efbdcec4..2289dbc20 100644
--- a/tests/PHPUnit/TestCase.php
+++ b/tests/PHPUnit/TestCase.php
@@ -33,6 +33,7 @@ class TestCase extends \PHPUnit\Framework\TestCase
 		});
 		when('get_plugin_data')->justReturn(['Version' => '1.0']);
 		when('plugin_basename')->justReturn('woocommerce-paypal-payments/woocommerce-paypal-payments.php');
+		when('get_transient')->returnArg();
 
 		when('wc_clean')->returnArg();
 		when('get_transient')->returnArg();