Update another scenario proxyAddress is removed

There is another scenario that guest users' proxyAddress is removed by conflicting contact object. This behaior is confired as by design in IcM 362139840

Author: juntakata

articles/active-directory/external-identities/troubleshoot.md

@@ -110,7 +110,7 @@ This happens when another object in the directory has the same invited email add
 
 ## The guest user object doesn't have a proxyAddress
 
-Sometimes, the external guest user you're inviting conflicts with an existing [Contact object](/graph/api/resources/contact). When this occurs, the guest user is created without a proxyAddress. This means that the user won't be able to redeem this account using [just-in-time redemption](redemption-experience.md#redemption-through-a-direct-link) or [email one-time passcode authentication](one-time-passcode.md#user-experience-for-one-time-passcode-guest-users).
+Sometimes, the external guest user you're inviting conflicts with an existing [Contact object](/graph/api/resources/contact). When this occurs, the guest user is created without a proxyAddress. This means that the user won't be able to redeem this account using [just-in-time redemption](redemption-experience.md#redemption-through-a-direct-link) or [email one-time passcode authentication](one-time-passcode.md#user-experience-for-one-time-passcode-guest-users). Also, if the contact object you're synchronizing from on-premises AD conflicts with an existing guest user, the conflicting proxyAddress is removed from the existing guest user.
 
 ## How does ‘\#’, which isn't normally a valid character, sync with Azure AD?
 
@@ -202,4 +202,4 @@ Let's say you inadvertently invite a guest user with an email address that match
 ## Next steps
 
 - [Get support for B2B collaboration](../fundamentals/active-directory-troubleshooting-support-howto.md)
-- [Use audit logs and access reviews](auditing-and-reporting.md)
+- [Use audit logs and access reviews](auditing-and-reporting.md)