ComplexTypeSystem.LoadAsync started throwing exception in the latest UA SDK.

[iconics-janb]

Hi all, I upgraded my client app to the latest UA SDK from Dec 18, 2025 recently. When connecting to UA CPP server by Unified Automation, I started getting exception when calling ComplexTypeSystem.LoadAsync. As a consequence, the complex types stopped working. The UA CPP server worked just fine with the previous version, I believe the server is OK, it also works fine with UA Expert.

Does anyone have the same problem? Is it a known issue?
Thanks.

The code in my client:

ComplexTypeSystem = new ComplexTypeSystem(session, new ComplexTypeBuilderFactory());
_ = await ComplexTypeSystem.LoadAsync(throwOnError: true, ct: ct).ConfigureAwait(false);

Exception thrown:

Opc.Ua.ServiceResultException
  HResult=0x80131500
  Message=Type system does not contain a valid data dictionary.
  Source=Opc.Ua.Client.ComplexTypes
  StackTrace:
   at Opc.Ua.Client.ComplexTypes.NodeCacheResolver.<LoadDataTypeSystem>d__12.MoveNext()
   at Opc.Ua.Client.ComplexTypes.ComplexTypeSystem.<LoadDictionaryDataTypesAsync>d__27.MoveNext()
   at Opc.Ua.Client.ComplexTypes.ComplexTypeSystem.<LoadAsync>d__14.MoveNext()
   at System.Runtime.CompilerServices.ConfiguredValueTaskAwaitable`1.ConfiguredValueTaskAwaiter.GetResult()
   at Ico.Fwx.UaClient.UaClientSession.<OpenSessionDirectAsync>d__55.MoveNext() in C:\_Git\FwxServerCore\IcoUaClient\Session\Session.cs:line 554

  This exception was originally thrown at this call stack:
    Opc.Ua.Client.ComplexTypes.NodeCacheResolver.LoadDataTypeSystem(Opc.Ua.NodeId, System.Threading.CancellationToken)
    Opc.Ua.Client.ComplexTypes.ComplexTypeSystem.LoadDictionaryDataTypesAsync(System.Collections.Generic.IList<Opc.Ua.INode>, bool, System.Threading.CancellationToken)
    Opc.Ua.Client.ComplexTypes.ComplexTypeSystem.LoadAsync(bool, bool, System.Threading.CancellationToken)
    System.Runtime.CompilerServices.ConfiguredValueTaskAwaitable<TResult>.ConfiguredValueTaskAwaiter.GetResult()
    Ico.Fwx.UaClient.UaClientSession.OpenSessionDirectAsync(Ico.OpcUa.Definitions.v1.OpcUaServer, System.Threading.CancellationToken) in Session.cs