Events+ Shortcodes break with WP3.6 upgrade?

I just upgraded the core WP install to 3.6, and it seems to have broken the shortcodes (see the top of the right sidebar on any page at http://equestcenter.org). Is this a known issue, and any advice on how to fix this? The site is fairly high profile and I'd like to get this working before the client notices. :disappointed:

[EDIT:] Correction, the widget appears to have been broken, not shortcodes. It just appears like broken shortcodes...long day here. :p