I need to add that I never saw this issue in my emacsclient sessions,
because in my config, I directly call (save-buffers-kill-emacs) if
(daemonp). So the (save-buffers-kill-terminal) never got executed when
running emacsclient with my config.

So I see this issue on emacsclient too if I do
M-x save-buffers-kill-terminal

So need to figure out what could cause that client parameter to be set to
"Unprintable entity".


-- 

Kaushal Modi