Hi,
I have the same issue!
I use wordpress 3.9.1 and jetpack 3.0.1.
I already tried to desactivate all the plugins but no related posts are showing!
Related posts is on but when i click on it in the setting’s jetpack page, i got this: “Warning: call_user_func_array() expects parameter 1 to be a valid callback, function ‘vaultpress_jetpack_more_info_connected’ not found or invalid function name…”
Do you have an idea?