I checked the calendar page and this looks like it might be a conflict with the Kornio theme where the theme has a similar script for generating tooltips. If we can narrow things down to confirm whether it’s a theme conflict or not we can troubleshoot further and put together a work around.
Here’s a quick and simple way to rule out a theme conflict:
1) You log into the site as admin, using the Safari browser
2) go to the page with the calendar (while logged in)
3) Click on the Customize link in the tool bar
4) Change the theme and preview the change only (do not click publish). You can change the theme to preview a theme like twentyfifteen or whatever option is there.
Once you’re viewing the preview the tooltips should appear if the issue is caused by a theme conflict.