chore: update polis entra scim logs to include custom attr info

docs/polis/directory-sync/providers/azure.mdx

@@ -74,13 +74,39 @@ From the right side of the screen, select the users you want to assign to the ap
 
 ## FAQ
 
-#### How frequently does Microsoft Entra ID SCIM perform sync by default?
+### How frequently does Microsoft Entra ID SCIM perform sync by default?
 
 Microsoft Entra ID automatically provisions and updates user accounts in an app based on things like user and group assignment.
 The sync happens at a regularly scheduled time interval, typically every 20-40 minutes.
 
-#### Why does the PATCH request fail in Microsoft Entra ID SCIM?
+### Why does the PATCH request fail in Microsoft Entra ID SCIM?
 
 This is a known issue with Entra ID SCIM implementation. You have to add the query param `?aadOptscim062020` to the SCIM endpoint
 URL to make PATCH requests work. This query param update PATCH behavior and ensure SCIM compliance.
 [Read More](https://learn.microsoft.com/en-us/entra/identity/app-provisioning/application-provisioning-config-problem-scim-compatibility#flags-to-alter-the-scim-behavior)
+
+### Why is a custom attribute not showing up in Ory Polis?
+
+If you map a custom attribute and it doesn't appear in the user record in Ory Polis, the cause is almost always on the Microsoft
+Entra ID side. Ory Polis stores every attribute it receives under the schema it arrives in, so a missing attribute means Entra ID
+didn't send it. Check the following in Microsoft Entra ID:
+
+- **The source attribute has a value.** Microsoft Entra ID
+  [doesn't provision null values](https://learn.microsoft.com/en-us/entra/identity/app-provisioning/customize-application-attributes#what-you-should-know).
+  If the mapped source resolves to empty (shown as `undefined` in the provisioning view), Entra ID sends nothing. Directory
+  extension attributes (`extensionAttribute1–15`) are often empty on cloud-only users and can only be set through Microsoft Graph
+  or Exchange, not the user profile page.
+- **The mapping applies to updates.** Set **Apply this mapping** to **Always** so the attribute flows on both create and update.
+  Entra ID only re-sends an attribute when its value changes, so change the value — or restart provisioning — to force a fresh
+  sync for users that already exist.
+- **Custom attributes may be sent on update, not on create.** Microsoft Entra ID can omit custom attributes from the initial
+  create (`POST`) and send them in a later update (`PATCH`). Use **Provision on demand** against a user that already exists to
+  trigger an update.
+- **Use a custom extension schema for non-standard attributes.** The enterprise extension schema
+  `urn:ietf:params:scim:schemas:extension:enterprise:2.0:User` is reserved for the RFC 7643 attributes (`employeeNumber`,
+  `department`, `manager`, and so on). Define your own attributes under a custom namespace such as
+  `urn:ietf:params:scim:schemas:extension:CustomExtensionName:2.0:User:CustomAttribute` through **Edit attribute list**.
+  [Read More](https://learn.microsoft.com/en-us/entra/identity/app-provisioning/customize-application-attributes#editing-the-list-of-supported-attributes)
+
+To see exactly what Microsoft Entra ID sends, open **Provision on demand** (or the **Provisioning logs**) in the Azure portal and
+review the **Modified attributes** for the user.