Edge case with ref forwarding doesn't throw an error when needed

## Description

Please see [my tweet](https://twitter.com/kripod97/status/1298016811364036608) for further details.

## Reproduction

Sandbox with all the information required: https://codesandbox.io/s/typescript-as-prop-with-react-polymorphic-box-vr269?file=/src/App.tsx

Start with the linked CodeSandbox reproduction, especially src/App.tsx, and read the linked tweet for the missing context. Reproduce the ref-forwarding edge case and trace the polymorphic component behavior to identify the expected error condition. Done means the reproduction raises the required error without breaking the documented polymorphic usage.

Written by the indexing model from the issue text.