While false casting, several times I managed to get my slack line (the part I hold in my left hand to shoot forward) wrapped around the bottom of the rod and reel. What did I do to make that happen?
If, when you release the line for the forward shoot, you release it into a donut formed by your thumb and index finger, it will usually shoot through the donut without tangling as Rip said.
The good thing about getting the tangles that you are getting is that you are getting good line speed - more than you need for the cast even.
Whoops: I mis-read your post. Sound like you are getting them while just false casting. I don't know what would cause that without seeing a video.