azure-pipelines-tasks: "Download Pipeline Artifacts" task fails on UNC artifacts

Type: Bug

Enter Task Name: “Download Pipeline Artifacts”

Environment

• Server - Azure Pipelines
• Agent - Private, 2.160.1

Issue Description

Using “Download Pipeline Artifacts” task to download UNC-base drop artifact results in error:

Microsoft.TeamFoundation.Build.WebApi.BuildArtifact is not of type PipelineArtifact, FileShare or BuildArtifact

The artifact was published using “Publish build artifacts” task.

Task logs

#[debug]Evaluating condition for step: 'Download Pipeline Artifact'
##[debug]Evaluating: succeeded()
##[debug]Evaluating succeeded:
##[debug]=> True
##[debug]Result: True
##[section]Starting: Download Pipeline Artifact
==============================================================================
Task         : Download Pipeline Artifacts
Description  : Download build and pipeline artifacts
Version      : 2.1.1
Author       : Microsoft Corporation
Help         : https://docs.microsoft.com/azure/devops/pipelines/tasks/utility/download-pipeline-artifact
==============================================================================
Download from the specified build: #375528
Download artifact to: D:\III\_work\71\s\
##[debug]Dedup parallelism: 192
##[error]Microsoft.TeamFoundation.Build.WebApi.BuildArtifact is not of type PipelineArtifact, FileShare or BuildArtifact
##[debug]Processed: ##vso[task.logissue type=error;]Microsoft.TeamFoundation.Build.WebApi.BuildArtifact is not of type PipelineArtifact, FileShare or BuildArtifact
##[debug]Processed: ##vso[task.complete result=Failed;]
##[debug]   at Agent.Plugins.PipelineArtifact.ArtifactProviderFactory.GetProvider(BuildArtifact buildArtifact)
   at Agent.Plugins.PipelineArtifact.PipelineArtifactServer.DownloadAsyncV2(AgentTaskPluginExecutionContext context, PipelineArtifactDownloadParameters downloadParameters, DownloadOptions downloadOptions, CancellationToken cancellationToken)
   at Agent.Plugins.PipelineArtifact.DownloadPipelineArtifactTaskV2_0_0.ProcessCommandInternalAsync(AgentTaskPluginExecutionContext context, CancellationToken token)
   at Agent.PluginHost.Program.Main(String[] args)
##[section]Finishing: Download Pipeline Artifact