If having a void session means no reckoning, and no meteors sent back to destroy Earth, how come a meteor coming to destroy Jane's house?

There was none! It was actually the comic PSYCHEing us with the Countdown, we see at the end of the Entry Process it wasn’t a meteor- It was Condy’s ship. That being said, while a Void Session doesn’t send all the Meteors in the Veil, it’d seem that either the main meteors ARE sent (The Frog Temple), or that Jade simply flung the Meteor Temple towards Skaia (As we see with the Troll’s Meteor, any approaching meteor is intercepted regardless of whether the Reckoning has started or not)