Comment 3 for bug 1815318

I believe this is just a different behavior in caja itself. You see, in both cases there is already a caja process running. In bionic's version, if you run caja again, it doesn't bring up a new copy, but instead uses the existing one to spawn the new windows:

ubuntu@bionic-mate:~$ ps fxaw|grep caja|grep -v grep
10308 ? Sl 0:01 \_ caja
ubuntu@bionic-mate:~$ caja
ubuntu@bionic-mate:~$ ps fxaw|grep caja|grep -v grep
10308 ? Sl 0:01 \_ caja
ubuntu@bionic-mate:~$ caja
ubuntu@bionic-mate:~$ ps fxaw|grep caja|grep -v grep
10308 ? Sl 0:01 \_ caja
ubuntu@bionic-mate:~$

But I have many new windows opened already.

In xenial, I do get new processes:
ubuntu@xenial-mate:~$ caja &
[1] 2764
ubuntu@xenial-mate:~$ Initializing caja-open-terminal extension
/usr/lib/python2.7/dist-packages/gi/overrides/Gtk.py:50: RuntimeWarning: You have imported the Gtk 2.0 module. Because Gtk 2.0 was not designed for use with introspection some of the interfaces and API will fail. As such this is not supported by the pygobject development team and we encourage you to port your app to Gtk 3 or greater. PyGTK is the recomended python module to use with Gtk 2.0
  warnings.warn(warn_msg, RuntimeWarning)
sys:1: PyGIWarning: Caja was imported without specifying a version first. Use gi.require_version('Caja', '2.0') before import to ensure that the right version gets loaded.
Initializing caja-main-menu extension
** Message: Initializing gksu extension...
ps fxaw|grep caja|grep -v grep
 2764 pts/8 Sl 0:00 \_ caja
 2338 ? Sl 0:00 \_ caja

This is definitely not a problem with openssh, and one could argue caja is behaving like intended, but I'll leave that for others to decide. Marking the openssh task as invalid.