It is happening to me exactly as you described it.
Re-start Vegas, play clips on the timeline and everything works fine. Then make some edits or move some clips or stop and start too fast by pressing “L” to play and Vegas stops working. The one thing I have noticed is that the Detail Report always shows the same fault location.
It is upon reopening the file that I find duplicate “Media effects” applied at the media level. I t may be related to the crash.