Tricks and traps for adding Ghostdoc documentation production to Azure Devops Build pipelines

I've studied the command line parameters for generating documentation and I've placed a batch script build step inside an existing devops pipeline which builds our code.

The documentation appears to build successfully, but fails on the final step with what looks like a .NET error:

Have I missed a trick here? Has anyone seen this kind of issue before?

Info: BuildAssembler: Building topic M:Rec.Biz.TriggerManagement.Change.UpdateTrigsCreate(DataTable,System.Byte[])
Generating help documentation...

Building web site index file...

Generating full-text index for the website...

Generating website...

Date and Time: 24/08/2020 15:14:28
IP Address: {0}
OS Platform: Win32NT
Processor: AMD64
OS version: 6.2.9200.0
Current user role: Administrator; User;

Allocated Memory: 77 Mb
Available Physical Memory: 1 Mb
Available Virtual Memory: 1 Mb
Total Physical Memory: 4096 Mb
Total Virtual Memory: 1280 Mb
Percentage of physical memory In use: 32 %

NET Framework version: 4.0.30319.42000

Visual Studio file: C:\Program Files (x86)\SubMain\GhostDoc Enterprise\SubMain.GhostDoc.Cmd.x64.exe
Visual Studio file version: 1.0.0.0

Application Domain: SubMain.GhostDoc.Cmd.x64.exe
Product Version: 20.2.20200.0
Assembly Codebase: file:///C:/Program Files (x86)/SubMain/GhostDoc Enterprise/SubMain.GhostDoc.Cmd.x64.exe
Assembly Version: 20.2.20200.0
Assembly Build Date: 18/07/2020 01:17:54
Assembly Full Name: SubMain.GhostDoc.Cmd.x64.clr4, Version=20.2.20200.0, Culture=neutral, PublicKeyToken=a4f99f6fdd8cefb6

Exception Source: mscorlib
Exception Type: System.ArgumentException
Exception Message: An item with the same key has already been added.
Exception Target Site: ThrowArgumentException

---- Stack Trace ----
System.ThrowHelper.ThrowArgumentException(resource As ExceptionResource)
SubMain.GhostDoc.Cmd.x64.exe: N 00060
System.Collections.Generic.Dictionary`2.Insert(key As TKey, value As TValue, add As Boolean)
SubMain.GhostDoc.Cmd.x64.exe: N 14338232
A.cba7a0ea294e9e174dfc17c379f5f490e.cfed9e056970d35d0a79eb0d099546f98( As XPathNodeIterator)
SubMain.GhostDoc.Cmd.x64.exe: N 00253
A.cba7a0ea294e9e174dfc17c379f5f490e.cd2b740a1514841cc14390745df2109a0( As ISolution, As String, As String, As IDoubleProgressMonitor, As String, As Boolean, As Int32&, As String)
SubMain.GhostDoc.Cmd.x64.exe: N 01769
A.cba7a0ea294e9e174dfc17c379f5f490e.cbd9be4288aa6c4bc190ab23d9ae14956( As Object, As Object, As ISolution, As String[], As String, As String, As IDoubleProgressMonitor, As Boolean, As Boolean)
SubMain.GhostDoc.Cmd.x64.exe: N 08361