Hi Evan,
Thanks for letting me know of this issue. I have fixed this and it will be updated in the next version which should be out soon. This was one of those small things I missed out. In the meantime, if you want you can try the below fix and get it working.
go to file plugins\eventON\admin\post_types\ajde_events_meta_boxes.php Line 884 and add '_evcal_ec_f3a1_cus', at the end of that line. (with quotation marks)
- Ashan