On Sep 19, 2017, at 09:36, Andreas Schwab <schwab@suse.de> wrote:

> $ stty; openssl aes-256-cbc -in foo.txt -out foo.text.enc; stty

Thanks, that’s exactly the clue I needed.

% stty
speed 9600 baud;
lflags: -echo echoe echoke echoctl
oflags: -oxtabs
cflags: cs8 -parenb
% sqlite3
SQLite version 3.16.0 2016-11-04 19:09:39
Enter ".help" for usage hints.
Connected to a transient in-memory database.
Use ".open FILENAME" to reopen on a persistent database.
sqlite> .exit
.exit
% stty
stty
speed 9600 baud;
lflags: echoe echoke echoctl
oflags: -oxtabs
cflags: cs8 -parenb
% stty -echo
stty -echo
|resist=|@resist[~:1020]% ls
Applications/	Library/	Sites/

Notice that -echo gets lost when exiting sqlite3.  Setting -echo explicitly fixes the problem.  So not a bug per se in Emacs, although I wonder if a coming-output-filter-function could be added to do the fix until the offending processes themselves are fixed?