Unable to install plugins from the web

[cartler-ctrl]

Whenever I click install on a plugin it will open up the Mod Manager.
I then click launch studio, but it gives me this error.

When I click "ok" it proceeds to launch studio as normal, but it never installs the plugin.

I have not tampered with "fast flags," nor do I know what they even do.
This is a fresh install of the latest release as of September 25th

Edit: Installing plugins within the studio plugin browser seems to work, so I will use that for now.