Efm breaks vim.lsp.buf.rename()?

main.py

def main():
    a_string = 'rename me!'

    return a_string


if __name__ == "__main__":
    main()

minimal_init.lua

-- install packer
local fn = vim.fn
local cmd = vim.cmd

local install_path = '/tmp/nvim/site/pack/packer/start/packer.nvim'

cmd('set packpath=/tmp/nvim/site')

local function load_plugins()
    local packer = require('packer')
    local use = packer.use

    packer.reset()
    packer.init {package_root = '/tmp/nvim/site/pack', git = {clone_timeout = -1}}

    use 'wbthomason/packer.nvim'
    use 'neovim/nvim-lspconfig'
    use 'kabouzeid/nvim-lspinstall'

    packer.sync()
end

_G.load_config = function()
    cmd('set termguicolors')

    -- Replace this part of the config with whatever configuration you're using
    require'lspinstall'.setup()
    require'lspinstall'.install_server('efm')
    require'lspinstall'.install_server('python')

    require'lspconfig'.python.setup {}
    require'lspconfig'.efm.setup {filetypes = {'python'}}

    vim.api.nvim_set_keymap('n', '<space>rn', '<cmd>lua vim.lsp.buf.rename()<CR>', {noremap = true, silent = true})
end

if fn.isdirectory(install_path) == 0 then
    fn.system({'git', 'clone', 'https://github.com/wbthomason/packer.nvim', install_path})
end

load_plugins()
cmd('autocmd User PackerComplete ++once lua load_config()')

load_config()

Run with nvim --noplugin -u minimal_init.lua main.py. Once both pyright and efm are downloaded, attempt to rename a_string using <space>rn. The dialogue will repeat itself. Afterwards, two changes are recorded.

It appears both language servers (pyright and efm) are being asked to rename the string, or that pyright is being asked twice? Removing efm fixes the issue.