Gateway region

The "gatewayregion" column in the "wvdconnections" table of Azure Monitor logs contains the name of the Azure region where the user's session host is located. An empty or "<>" value in this column indicates that the region information is not available for that particular connection.

There could be several reasons why the gatewayregion value is empty or "<>" for some AVD connections:

The user's session host is not located in an Azure region that is recognized by the system.
The region information was not captured or logged properly during the connection process.
The connection was established through an alternate gateway or protocol that does not provide region information.
To troubleshoot this issue, you can check the Azure Monitor logs for any errors or warnings related to the connection process. You can also try connecting to the session host directly and see if the gatewayregion value is populated correctly