diff --git a/src/server/auth/handlers/register.ts b/src/server/auth/handlers/register.ts
index 7eca5b17..2a74b4a4 100644
--- a/src/server/auth/handlers/register.ts
+++ b/src/server/auth/handlers/register.ts
@@ -84,16 +84,17 @@ export function clientRegistrationHandler({
         : undefined;
       const clientIdIssuedAt = Math.floor(Date.now() / 1000);
 
+      // Calculate client secret expiry time
+      const clientsDoExpire = clientSecretExpirySeconds > 0
+      const secretExpiryTime = clientsDoExpire ? clientIdIssuedAt + clientSecretExpirySeconds : 0
+      const clientSecretExpiresAt = isPublicClient ? undefined : secretExpiryTime
+
       let clientInfo: OAuthClientInformationFull = {
         ...clientMetadata,
         client_id: clientId,
         client_secret: clientSecret,
         client_id_issued_at: clientIdIssuedAt,
-        client_secret_expires_at: isPublicClient 
-          ? clientSecretExpirySeconds > 0 
-            ? clientIdIssuedAt + clientSecretExpirySeconds 
-            : 0
-          : undefined,
+        client_secret_expires_at: clientSecretExpiresAt,
       };
 
       clientInfo = await clientsStore.registerClient!(clientInfo);