Shell echoing every command

(xpost from Unix Stack Exchange)

I'm using a local shell via an Emacs shell buffer. Seemingly at random, my shell will start echoing back every command I type before the rest of the output.

h ~ $ pwd
pwd
/Users/ericauld
h ~ $ echo $-
echo $-
himBCH
h ~ $ bash --version
bash --version
GNU bash, version 5.2.21(1)-release (aarch64-apple-darwin23.0.0)
h ~ $ trap
trap

Notice that neither xtrace (-x) or verbose (-v) are set.

Often I can get it to stop by restarting the shell.

h ~ $ pwd
pwd
/Users/ericauld
h ~ $ exit
exit
exit

Process shell<1> finished
h ~ $ pwd
/Users/ericauld
h ~ $ 

I notice there are two echoed exits above, which could be a clue.

It seems to happen often, but not always, after I enter and exit a pdb session.