Karl.. the only way to be sure the bit didn't slip is to check it before the cut and see how far below the router it is, then again afterwards.
I had used a PC router for years before I got my SB and was surprised that the bits slipped with the SB. The reason appears to be the CNC motion system can push into the material harder and faster than a person would, so the bit experiences heavier cut forces.
First thing to do is measure the bit and be sure its not slipping. If its not, then we can talk about other possible causes.
Good luck, and welcome!
D
"The best thing about building something new is either you succeed or learn something. Its a win-win situation."
--Greg Westbrook