update FP section

add FP note for new or existing connections

Author: raghavendermareddy

articles/expressroute/expressroute-howto-linkvnet-arm.md

@@ -5,7 +5,7 @@ services: expressroute
 author: duongau
 ms.service: azure-expressroute
 ms.topic: how-to
-ms.date: 03/26/2025
+ms.date: 03/31/2025
 ms.author: duau
 ms.custom: devx-track-azurepowershell
 ---
@@ -233,6 +233,9 @@ The range of *RoutingWeight* is 0 to 32000. The default value is 0.
 ## Configure ExpressRoute FastPath 
 You can enable [ExpressRoute FastPath](expressroute-about-virtual-network-gateways.md) if your virtual network gateway is Ultra Performance or ErGw3AZ. FastPath improves data path performance such as packets per second and connections per second between your on-premises network and your virtual network. 
 
+> [!NOTE]
+> When you enable FastPath on new or existing connections, the FastPath routes are programmed after the connection between the ExpressRoute Gateway and the ExpressRoute Circuit is established. This will briefly route on-prem traffic via the ExpressRoute Gateway.
+
 **Configure FastPath on a new connection**
 
 ```azurepowershell-interactive