Completion cannot use pum#next

[A4-Tacks]

Result from CocInfo

## versions

vim version: VIM - Vi IMproved 9.1 9011362
node version: v23.9.0
coc.nvim version: 0.0.82-13d0416 2025-07-31 16:32:31 +0800
coc.nvim directory: /home/lrne/.vim/plugged/coc.nvim
term: dumb
platform: linux

## Log of coc.nvim

2025-08-22T16:32:08.892 INFO (pid:20940) [plugin] - coc.nvim initialized with node: v23.9.0 after 395
2025-08-22T16:32:08.895 INFO (pid:20940) [services] - LanguageClient Json language server state change: stopped => starting
2025-08-22T16:32:08.911 INFO (pid:20940) [language-client-index] - Language server "json" started with 20959
2025-08-22T16:32:09.057 INFO (pid:20940) [services] - LanguageClient Json language server state change: starting => running
2025-08-22T16:32:09.071 INFO (pid:20940) [services] - service json started
2025-08-22T16:32:14.088 INFO (pid:20940) [attach] - Request action: stopCompletion [ '' ]
2025-08-22T16:32:15.145 INFO (pid:20940) [attach] - receive notification: startCompletion [ {} ]
2025-08-22T16:32:16.493 INFO (pid:20940) [attach] - Request action: stopCompletion [ 'confirm' ]
2025-08-22T16:32:19.235 INFO (pid:20940) [attach] - Request action: stopCompletion [ '' ]

Describe the bug

• coc#pum#next unexpected close completion pum
• coc#pum#confirm() unexpected lose chars

Reproduce the bug

We will close your issue when you don't provide minimal vimrc and we can't
reproduce it

• Create file mini.vim with：

  coc-settings.json:

  {}

  colorscheme habamax
  
  set nu
  set laststatus=2
  set statusline=%<%f\ %h%m%r%=%-14.(%l,%c%V%)\ %P
  set statusline^=%(%1*[%{coc#status()}%{get(b:,'coc_current_function','')}]%*\ %)
  
  call plug#begin('~/.vim/plugged')
  Plug 'neoclide/coc.nvim'
  call plug#end()
  
  inoremap <silent><expr> <cr>
              \   coc#pum#visible() ? coc#pum#confirm()
              \ : "\<C-g>u\<CR>\<c-r>=coc#on_enter()\<CR>"
  inoremap <silent><expr> <tab> coc#pum#visible()
              \   ? coc#pum#next(0)
              \   : coc#refresh()
  nmap <F3> <Plug>(coc-codeaction-cursor)
  nmap <C-k> <Plug>(coc-diagnostic-prev)
  nmap <C-j> <Plug>(coc-diagnostic-next)

• Start vim with command: vim -Nu mini.vim ~/.vim/coc-settings.json

• Operate vim.

  1. startinsert in {}
  2. input "inlayHint -> {"inlayHint}
  3. leaveinsert and close completion pum
  4. insert and cursor (|) at {"inlayHint|}
  5. input <tab> select inlayHint.position~
  6. input <cr> confirm
  7. output {"inlayHint.position": |, completion pum is visible
  8. input <tab> try coc#pum#next, but completion pum unexpected closed

  Expect output: {"inlayHint.position": |}, and completion is visible

If applicable, add screenshots to help explain your problem.