It looks like you have carved across nearly the entire with of the board, leaving only a fraction of an inch of material under the rollers when cutting.
I have virtually eliminated problems like this since using a sled, which I use for every project 12" wide or less. My sled is 3/4" plywood with 1" rails and 4" end caps. In addition to adhering to the 7" rule, the rails ensure good contact with the rollers even if the entire width of the project board is carved away. It keeps the cutting bit away from the brass roller which otherwise can induce vibration and cause tracking errors. The mass of the sled also reduces vibration.