I think I got it. Because I wanted a lot of detail in the mask I created a lot of anchors. Thing is if I just move the anchors around everything is ok, but when I use the split tangent tool it crashes. So I tried deleting a previously made anchor and then using the split tangent tool and it didn’t crash. But when I tried adding another anchor it crashed again. As long as I keep deleting anchors and creating new ones it does not crash.
Does Vegas have an anchor cap for the masks or what?