Test-ModuleManifest Tag property stacks

Prerequisites

• Write a descriptive title.
• Make sure you are able to repro it on the latest released version
• Search the existing issues.
• Refer to the FAQ.
• Refer to Differences between Windows PowerShell 5.1 and PowerShell.

Steps to reproduce

Test-ModuleManifest Tag property stacks

Didn't have time to review completly please confirm.

Check in master an may spoted the bug. Please see Error Details

$data = Test-ModuleManifest -Path "$PackageManifest"
Write-Host "$($data.Tags.Count)"
$data = Test-ModuleManifest -Path "$PackageManifest"
Write-Host "$($data.Tags.Count)"
$data = Test-ModuleManifest -Path "$PackageManifest"
Write-Host "$($data.Tags.Count)"
$data = Test-ModuleManifest -Path "$PackageManifest"
Write-Host "$($data.Tags.Count)"
$data = Test-ModuleManifest -Path "$PackageManifest"
Write-Host "$($data.Tags.Count)"
$data = Test-ModuleManifest -Path "$PackageManifest"
Write-Host "$($data.Tags.Count)"

Expected behavior

2
2
2
2
2
2

Actual behavior

...
50
52
54
56
58
60
...

Error details

Please review in ModuleCmdletBase.cs
Line 3225 till 3236

In conjunction with PSModuleInfo.cs
Line 318 till 356

Environment data

Name                           Value
----                           -----
PSVersion                      5.1.19041.1682
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.19041.1682
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1

Visuals

No response

Start by reproducing the repeated Test-ModuleManifest calls and checking that the tag count grows instead of remaining at 2. Read ModuleCmdletBase.cs lines 3225-3236 alongside PSModuleInfo.cs lines 318-356, then verify the behavior against the expected repeated counts shown in the issue.