PiXYZ plugin 2018.3.1.r4 not working in build.

I am using latest PiXYZ plugin (2018.3.1.r4) on latest version on Unity (Unity 2018.3.0f2 (64-bit) on a system with PiXYZ licence. I simply imported package and built the ImportOnPlay scene. The scene is working fine in Unity, but in build it is not importing any model. Also, when I imported the package, I got this error:

The method or operation is not implemented.
System.Environment.FailFast (System.String message)

Sceenshot has been attached.

I’m getting this exact error as well using 2018.3.1f1 using a completely different plugin. (Pro Radar) Other dll’s work fine, but this one specific .dll throws these errors every time something reloads.

When swapping the unity project to the .NET 3.5 scripting runtime, the errors no longer show up. Using that as a base I figured maybe I could get the DLL to be recompiled targeting 4.x, but Unity doesn’t seem to support editor plugins targeting 4.x…

I wish I could give more information, but that’s all I got.

I have this exact issue in Unity 2018.4.3.1 and using PiXYZ dll, when I uninstall the package error goes away.