.NET API OPC DA Client sometimes fails to Read() and GetProperties()|Classic OPC: DA, A&E, HDA, XML-DA, etc.|Forum|OPC Foundation

Hello, I recently started to implement an OPC Classic DA client using NET API. However, some items/nodes cannot be successfully Read() or GetProperties(). However other client can read the same items/nodes successfully, such as Softing ToolBox OPC Classic client. I printed out some debug logs:

Failed Read() and GetProperties(), I understand, when the flag BrowseElement.IsItem is False, Read() won’t work. But even some of the properties were failed to read: Property.Value, Quality and Timestamp.

–Item Name: \\SESSION\APL_NR
–Item Path:
–Is Item: False
–Has Children: False
–Properties: Opc.Da.ItemProperty[]
|ID |Value |DataType |Description |Result
dataType (1): System.Int32: System.Int16: Item Canonical DataType: S_OK
value (2): : System.Int32: Item Value: E_UNKNOWN_ITEM_NAME
quality (3): : System.Int16: Item Quality: E_UNKNOWN_ITEM_NAME
timestamp (4): : System.DateTime: Item Timestamp: E_UNKNOWN_ITEM_NAME
accessRights (5): readable: System.Int32: Item Access Rights: S_OK
scanRate (6): 0: System.Single: Server Scan Rate: S_OK

This Node can be browsed and read correctly.
–Item Name: \\APL\1\P\AUTOMATIONADAPTER\1
–Item Path:
–Is Item: True
–Has Children: False
–Properties: Opc.Da.ItemProperty[]
|ID |Value |DataType |Description |Result
dataType (1): System.Int32: System.Int16: Item Canonical DataType: S_OK
value (2): 1: System.Int32: Item Value: S_OK
quality (3): good: System.Int16: Item Quality: S_OK
timestamp (4): 27/06/2024 12.54.10: System.DateTime: Item Timestamp: S_OK
accessRights (5): readWritable: System.Int32: Item Access Rights: S_OK
scanRate (6): 0: System.Single: Server Scan Rate: S_OK
5001: 0: System.Int32: AA Action Activation: S_OK
5002: 0: System.Int32: AB Alarm Blocking: S_OK
5003: 0: System.Int32: AC Alarm Class: S_OK
5004: 0: System.Int32: AD Alarm Delay: S_OK
5005: 0: System.Int32: AE Action Enabled: S_OK
5006: 0: System.Int32: AF Action at First Update: S_OK
5007: 1: System.Int32: AG Alarm Generation: S_OK
ItemName: \\APL\1\P\AUTOMATIONADAPTER\1 Value: 1  Timestamp:27/06/2024 12.54.10 DataType: System.Int32