Please try this fix. It modifies the script in /usr/sbin/wifi.sh
by adding a 3 second pause before disconnecting
the network. You can edit the script yourself with nano
editor as root by adding a "sleep 3" coomand after this
if statement:

if [ `echo "$out" | grep -c RUNNING` -gt "0" ] ; then
# ADD IT HERE
sleep 3
run-standalone.sh dbus-send --system \
--dest=com.nokia.icd /com/nokia/icd_ui com.nokia.icd_ui.disconnect boolean:true
fi

Let me know if it helps. Eventually increase the value to 4 or 5
or more to see if it makes any difference.

BTW: what happens if you go to the connection manager instead and disable the connection from there? Does it reboot the same.
If yes file a bug at the cutetube-qml people.