When it is happening, make sure the brake lights are working, if not, the brake light switch may be out of adjustment or starting to fail. However, the most common problem with these is that the shift lock micro-switch fails. The switch would need to be removed and the resistance checked. If it is over .5 ohms of resistance when the switch is closed, it is bad. But, if someone is going to go to the trouble of pulling apart the shift console to check it, just replace it anyway, but still check it to verify it was the cause of the problem.