Why is Illustrator loading plugins from a non-standard location?

Illustrator 27.3.1 (Windows)

A plugin error comes up when Illustrator is launched.

It turns out this plugin resides in C:\Vision Pro 9 which is the installation folder for a different software package that runs a CNC machine.

First of all, why is Illustrator even attempting to load plugins from this folder in the first place?

If I rename IlluToSignlab32.aip to IlluToSignlab32.aip.DISABLE, effectively hiding it, Illustrator won't even launch.

Clicking Ok and relaunching gives the option to Run Diagnostics (i.e. Safe Mode). While launching in Safe Mode the same unknown error dialog box comes up and Illustrator still won't launch. Any subsequent launches just bring up the same unknown error dialog box. So Safe Mode is basically useless in this case.

On further testing if I don't rename the plugin but instead move it to the desktop, Illustrator still tries to load it from the desktop. It seems as if Illustrator is loading .aip files from anywhere and everywhere. It was my understanding that plugin needed to be in C:\Program Files\Adobe\Adobe Illustrator 2023\Plug-ins in order to be seen. Has this behavior changed? Is there any documentation on it? I can't find any.

In any event it's bizzare and frustrating that some 3rd party plugin that shouldn't even be recognized is causing so many problems with Illustrator.