Failed to connect to session manager: Failed to connect to the session manager: SESSION_MANAGER environment variable not defined when given

I am starting xfce4-terminal from cron like this:

env DISPLAY=':0.0' SESSION_MANAGER='' xfce4-terminal --disable-server --command  "bash -c 'reset ; for (( i=0 ; i<10 ; i
++ )) ; do echo $i ; sleep 1 ; done'"

Even though --disable-server is given, xfce4-terminal, seemingly, tries to connect to dbus, and when failing, complains:

Failed to connect to session manager: Failed to connect to the session manager: SESSION_MANAGER environment variable not defined when given

Note the repeated text: Failed to connect to session manager:

The terminal waits for the command to finish, so some of the '--disable-server' functionality is implemented correctly, but, apparently, some dbus machinery is still invoked.