Hey @drawcall!
Getting the above warning when my scene loads.
Don't even using anything from Proton, I'm only importing it and some class from three that I'm using:
import { Object3D, Vector3 } from "three"
// @ts-ignore
import Proton from "three.proton.js"
Tried with import * as THREE from "three" as well, same result.
My three version is 0.166.1