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'

Inizia riproducendo l’errore di riferimento null con il modulo PowerShell segnalato e PSScriptAnalyzer 1.21.0, confrontando le esecuzioni normali e -Verbose di Invoke-ScriptAnalyzer. Restringi il problema a una funzione o a un’operazione specifica dell’analizzatore usando le versioni del modulo e dello strumento di build elencate nel report; il lavoro è completato quando la causa è stata identificata e l’eccezione viene impedita senza richiedere un output dettagliato.