Can’t add timeslots for more than one site in WPMU Network

I have the plugin network-enabled for a set of event sites we have created as wordpress network (WPMU). Everything works great for the first site I create a timetable on, but for all other sites when you hit publish or update on an event, it clears the timeslots list – preventing the event from showing in the timetable. No errors are shown. Any thoughts?

Steps to reproduce:

1) Setup a wordpress multisite network
2) Install and network-enable the mp-timetable plugin
3) Create a new site in the network
4) Add at least one column
5) Add a new event with a Timeslot
6) Click Publish (Works fine – Timeslot appears)
7) Create a second site in the network
8) Add at least one column on the new site
9) Create a new event in the new site with a timeslot
10) Click Publish (Timeslot Disappears)

Result: Timeslot disappears when event is published on all but the first site containing events. If you add or edit events on the first site, timeslots continue to work properly.