That's a message from hook processing. I normally turn this off in the zmeventnotification.ini file, but it was left on and causes that message:
# send event end notifications (default: no)
# Note that if you are using hooks for end notifications, they may change
# the final decision. This needs to be yes if you want end notifications with
# or without hooks
send_event_end_notification = no
Be sure it's set to no. For some reason pliablepixels sets it to yes in the ES release.