Add solution suggested by @fhammerl

src/Runner.Common/JobServerQueue.cs

@@ -818,7 +818,6 @@ namespace GitHub.Runner.Common
 
             return mergedRecords;
         }
-
         private async Task UploadFile(UploadFileInfo file)
         {
             bool uploadSucceed = false;

src/Sdk/DTObjectTemplating/ObjectTemplating/TemplateContext.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Linq;
@@ -163,7 +163,6 @@ namespace GitHub.DistributedTask.ObjectTemplating
                 message = $"{prefix} {message}";
             }
 
-            Errors.Add(message);
             TraceWriter.Error(message);
         }