Object reference not set to an instance of an object.

Good morning,
I have a PowerShell module at work with almost 400 functions. Recently I switched from PSScriptAnalyzer version 1.13.0 to version 1.21.0, fixed a lot of problems, but I have one left. On random functions I get the error:

Exception: Object reference not set to an instance of an object.

If I use the Invoke-ScriptAnalyzer function with the -Verbose switch, the error does not occur. I discovered this by accident while looking for which function is causing the error.

Please advise how to trace the cause.
Somewhere I found information that this can be caused by the Export-ModuleMember function, but I don't want to get rid of it because I would have to fiddle with building the manifest file and that's how Psake does it for me.

For building and checking a powershell module I use
TeamCity and
Psake = '4.9.0'
Pester = '5.3.3'
BuildHelpers = '2.0.16'
PSScriptAnalyzer = '1.21.0'
PSDepend = '0.3.8'

報告されている PowerShell モジュールと PSScriptAnalyzer 1.21.0 を使って null 参照エラーを再現することから始め、通常の Invoke-ScriptAnalyzer 実行と -Verbose を付けた実行を比較します。報告に記載されているモジュールとビルドツールのバージョンを使って、失敗箇所を特定の関数またはアナライザー操作まで絞り込みます。原因を特定し、詳細な出力を必要とせずに例外を防止できれば完了です。