Thanks again Casey,
I installed a brand new WordPress (3.6.1) instance with default theme and added both, The Events Calendar (3.1) and Community Events (3.1). Same old story. Whenever I choose existing organizer or venue when posting new event suggestion, the name, address and all the other information goes blank.
Personally I don’t understand why your plugin even tries to update venue and organizer information “on-the-fly” when posting new events / suggestions from the public site. Especially if the registration is not required as it’s not in my project.
However, I got tired of playing around with this problem so I hacked my own hooks & functions to prevent overriding venues and organizers with blank data.