This is also happening to me on two different sites, using two different themes (including the default theme).
Older version – http://downloads.wordpress.org/plugin/jetpack.1.2.2.zip
Same thing at texasmusicaltheatreworkshop.com
Rolling back now.
Same here, I’m using Suffusion 4.x and lost my “magazine” template home page had to disable Jetpack
Plugin Contributor
James Huff
(@macmanx)
Volunteer Moderator
Sorry about that! This is all fixed now, please update to Jetpack 1.2.4.
Yesterday I updated to Jetpack 1.2.4 and this is clearly not all fixed as my website comes up blank (except for the header and nav menu) when Jetpack is activated. Even though I have it deactivated now, something still seems to be interfering with my other plugins. I posted here: http://wordpress.org/support/topic/jetpack-ruined-my-site?replies=2
Help or some kind of update would be appreciated.