How to remap shortcut ?

[945fc41467]

I am not sure if it is a coc or a coc-ltex issue.

When i use coc for autocompletion, I remaped <c-t> and <c-s> (i use a bépo layout, so the keys are at the same position than j and k on qwerty keyboard) to go to next and prev items : 

inoremap <silent><expr> <c-u> coc#refresh()
cnoremap <c-t> <c-n>
cnoremap <c-s> <c-p>
inoremap <silent><expr> <c-t>
       \ coc#pum#visible() ? coc#pum#next(1) :
       \                     CheckBackspace() ? "\<c-t>" :
       \                                        coc#refresh()
inoremap <silent><expr> <c-s> coc#pum#visible() ? coc#pum#prev(1) : "\<c-s>"
inoremap <silent><expr> <tab> coc#pum#visible() ? coc#pum#next(1) : "\<tab>"

function! CheckBackspace() abort
  let col = col('.') - 1
  return !col || getline('.')[col - 1]  =~# '\s'
endfunction

but for a reason I don’t understand, it works as expected with completion, but not with spell check. With spell check it use j and k or <c-n> and <c-p>. qwerty’s t and s don’t work to. So it is probably not a problem of keyboard layout. It just seems coc-ltex use a different configuration than coc. Must coc-ltext shortcut be configured in a different way ?