Unable to Compile Package with Script Tasks or Components

I am unable to compile any biml packages with script tasks or components. The error is similar to:
    
Expanding Biml
1/1 Emitting Project Package2.dtproj.
1/1 Emitting Package Package2.
Error 0 The type or namespace name 'Data' does not exist in the namespace 'System' (are you missing an assembly reference?). In Script Project 'TaskScriptProject1': \ScriptMain.cs 3 23
Error 0 The type or namespace name 'Windows' does not exist in the namespace 'System' (are you missing an assembly reference?). In Script Project 'TaskScriptProject1': \ScriptMain.cs 5 23
Error 0 The type or namespace name 'ApplicationSettingsBase' does not exist in the namespace 'System.Configuration' (are you missing an assembly reference?). In Script Project 'TaskScriptProject1': \Designer\Settings.designer.cs 15 75
Error 0 The type or namespace name 'ComponentModel' does not exist in the namespace 'System' (are you missing an assembly reference?). In Script Project 'TaskScriptProject1': \Designer\Resources.designer.cs 42 25
Error 0 The type or namespace name 'ComponentModel' does not exist in the namespace 'System' (are you missing an assembly reference?). In Script Project 'TaskScriptProject1': \Designer\Resources.designer.cs 59 25
Error 0 The type or namespace name 'CodeDom' does not exist in the namespace 'System' (are you missing an assembly reference?). In Script Project 'TaskScriptProject1': \Designer\Resources.designer.cs 25 21

I am trying on both vs2017 and vs2019. I am using the latest bimlexpress.vsix. I am on Windows 10.
    
I am guessing I have a path issue or something? 
Removing and reinstalling the .vsix works for a little while, but this is not a sustainable option. 
The last four errors are for an internal part of the script that I have no control over. 

Where does this get its references from?

The code being referenced is generated internally within the compiler engine. That code is then dynamically compiled to produce an assembly that is serialized into the DTSX file. This is done to match the behavior of the script project UI in SSDT.

These errors indicate that when the compiler engine attempts to compile the generated code, it is not able to locate key assembly references - including those in the .NET framework itself. 
This is not an error we have observed nor heard reported from others.

Based on the fact that reinstallation of the extension eliminates the issue for some time and the fact that this is an assembly resolution issue deep within the core engine, we suspect that there is something happening on your system to corrupt the installation.

The next time this issue arises, can you backup the BimlExpress installation folder prior to uninstall. 
Then reinstall the add-in and compare the new installation folder to the backed up folder. 
This should identify what changed and help to locate the source of the corruption. You will find all Visual Studio extensions installed to a randomly named sub-folder in the following folder:

%LOCALAPPDATA%\Microsoft\VisualStudio\VSVERSION\Extensions

(where VSVERSION is replaced with the version number of Visual Studio you are using).

We cannot be certain of issue without a minimal code example. Most likely, this is due to missing assembly references in your code. Be sure to supply the necessary assembly references in the "AssemblyReferences" element of your script project tag.

This is the relevant documentation: https://docs.varigence.com/biml-reference/language-reference/Varigence.Languages.Biml.Script.AstTaskScriptProjectNode

-Varigence Support