Flickering on hover when using Menu (Dropdown)

[accacin]

I have copied the styled example from right at the top of the page, here: https://headlessui.com/react/menu

When using the said example (minus the fixed CSS class), the menu works and looks as expected, but when hovering the menu entries in Firefox I get some fast flickering as shown below.

Screencast.from.17-10-22.21.24.30.webm

I've played around and I'm unable to get the flickering to stop. I have tested in Chromium and the same behavior doesn't happen. My main suspicion was the transitions, but removing these didn't seem to help either.

Using latest React, headlessui, etc.

If it helps, the project I'm working on is here