BUG - Select (dropdown) flashing and closing on click in Firefox

On MacOS running Firefox - when clicking on the select drop down, the list flashes and then disappears.

Confirmed the same action using the demo provided: [https://final-form.org/docs/react-final-form/examples/simple](https://final-form.org/docs/react-final-form/examples/simple)

Demo video here: [https://www.loom.com/share/df64321f80334d9489114a538addf9ee](https://www.loom.com/share/df64321f80334d9489114a538addf9ee)

In my app it happens both in the text area and the down arrow.. in the sample it only does it in the down arrow area for some reason.

### What is the expected behavior?

On clicking the select input it should display the list and stay on the screen until the user selects an item in the list or clicks out.

### What's your environment?

MacOS 10.15.6
Firefox 80.0b8 (64-bit)

In my app:
"final-form": "4.20.1",
"final-form-arrays": "3.0.2",
"react-final-form": "^6.5.1",
"react-final-form-arrays": "3.1.2",
"node": "12.x"

It appears to work fine in Safair and

Newbie to this stuff, so please excuse me for missing infomation etc. Ask me for what you need and I will do my best to get it to you.