Random error linked to Coc.nvim prevents from saving on exit

[Cudochi]

Hello,
I have this error message popping from time to time.
It seems to be linked to Coc.nvim, but I haven't managed to narrow down the conditions of reproduction. Getting it means the session won't be saved.

Could you give me some pointers ?

Error detected while processing Autocommands VimLeavePre for "*"..function coc#rpc#request[4]..<SNR>46_request[34]..Autocommands VimLeavePre for "*"..function coc#rpc#request[4]..<SNR>46_request :           
line 31 :
E605: Exception not caught : Error on request: Vim(return):Error invoking 'doAutocmd' on channel 3 (coc):^@Vim(mksession):E190: Unable to open "/home/test/.local/share/nvim/sessions/mod_bundle/config.lu
ahomemod_bundle/config.luatestmod_bundle/config.lua.configmod_bundle/config.luanvim.vim" to write in it
Press ENTER or type a command to continue 

With regards.