When a modal is open, double-clicking on the background overlay results in the modal disappearing then quickly reappearing again with the following warning in the console:

react_devtools_backend.js:6 React-Modal: Cannot register modal instance that's already open 
    at ModalPortal (http://localhost:4500/static/js/0.chunk.js:60569:5)
    at Modal (http://localhost:4500/static/js/0.chunk.js:60212:5)

Additionally, the ReactModal__Body--open class remains on the body after closing the re-opened modal.