This is the second this has happened to me...I baked a 1/2 sheet chocolate cake from the confetti cakes decorating book (last time this happened it was a vanilla pound cake) and when i took it out of the pan and flipped it out onto parchment paper there are random craters in the bottom?? does anyone know why this happens??

I learned a long time ago to gently drop the pans on the table several times to settle the batter and eliminate air bubbles before baking. Just cover the table with several towels to keep the noise reduced. HTH