I don't mean to speak for Kayak, but if you don't mind my interpretation....to get around tight corners, or changing directions sharply, I "walk" the machine by hand turning the wheel, with a little help from the motor.....but before I lift the foot to rearrange the leather piece, I make sure the needle is in the upward stroke position so it's picked up the bobbin thread.....if the needle is not in the upward stroke and has not picked up the bobbin thread, you'll have an empty hole, with no thread through it......
Kayak and others will have the proper terminology to explain what goes on, but it's just how I explain it.