Coc.nvim: closing floating window with a split window closes current window

Result from CocInfo

## versions

vim version: NVIM v0.4.4
node version: v12.19.0
coc.nvim version: 0.0.79-80ae19dee6
coc.nvim directory: /Users/matthieu.arene/.local/share/nvim/plugged/coc.nvim
term: iTerm.app
platform: darwin

Describe the bug

When a split window (or a tab) is open, and a coc floating window pops up (for example when the cursor gets placed on a warning, or when the documentation of a symbol gets consulted), if the cursor is moved, then the current window is closed.
(see screenshot section for more clarity).

This baffles me because I had close to exactly the same nvim/coc setup on my previous work macbook three days ago, and it worked just fine: I possibly done a stupid configuration mistake, but I just cannot find it.

Reproduce the bug

• Create file mini.vim with：

  set nocompatible
  set runtimepath^=/Users/matthieu.arene/.local/share/nvim/plugged/coc.nvim
  filetype plugin indent on
  syntax on
  set hidden
  call plug#begin(stdpath('data') . '/plugged')
  Plug 'neoclide/coc.nvim', {'branch': 'release'}
  call plug#end()
  

• Start (neo)vim with command: vim -u mini.vim

• Open a split window, in one of those windows navigate to a warning (or hover over a documented symbol). Once a floating window pops up, move the cursor and the current window will close

Screenshots