Poweshell buidl script runs into error MSB1001

[ghostravenstorm]

Problem:
Poweshell build script runs into error MSB1001.
Preparing to run build script...

Running build script...
Could not load H:\storage\vcom3d\amm\repos\rticommunity\rticonnextdds-connector-cs\tools\Addins\altcover.api.5.0.663\lib\net45\BlackFox.CommandLine.dll (missing FSharp.Core, Version=4.4.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
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Build-API
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Microsoft (R) Build Engine version 4.8.4084.0
[Microsoft .NET Framework, version 4.0.30319.42000]
Copyright (C) Microsoft Corporation. All rights reserved.
MSBUILD : error MSB1001: Unknown switch.
Switch: /warnaserror
For switch syntax, type "MSBuild /help"
An error occurred when executing task 'Build-API'.
Error: One or more errors occurred.
        MSBuild: Process returned an error (exit code 1).

How to reproduce:
Grab any Windows system (fresh isntall preferred).
Install Visual Studio with .NET desktop dev environment and F# desktop language support
Clone or fork the repo and follow the setup instructions in the readme
Init submodule
Run powershellscript
Observe error MSB1001

Expectation:
Error MSB1001 should not be occuring.