By definition an unproxified object's method is not under our control. If the method expects an argument, and that argument happens to be wrapped in Proxy, it may fail in an implementation dependent way.
How can we prevent this?
Example
// device has type 'Proxy(GPUDevice)'
const buf = await device.createBuffer(...); // Proxy(GPUBuffer)
const range = buf.getMappedRange(); // Proxy(Float32Array)
new Float32Array(range); // creates an empty array due to the constructor's incompatibility with Proxy