iTerm2 printing out a null character

Question

Every time a command I issue from iTerm2 takes longer than a minute to complete, a null character ^@ gets printed out once for every minute or so continuously until the process completes.

I can't figure out if this is a bug or a feature that I should somehow be able to disable.

It actually seems to print out to the terminal, but it is not going to either stdout or stderr:

$ echo `sleep 181`
^@^@
$ echo `sleep 181` 2> /tmp/stderr
^@^@
$ echo `sleep 181` > /tmp/stdout
^@^@

Answer 1

Turn off "when idle send ascii code" in prefs->profiles->session.