I'm having this problem, it's done this now on two videos I have tried to mask. With the first I thought it may have been an issues with the source having blended frames but now that it's happening again I really don't know.. Hopefully it's something stupid someone can point out for me.
So I go frame by frame masking out my scene and when I get to the next frame the mask from the previous frame appears and will not go away.
This is a SS of the character as I have him masked in vegas
This is a SS of the preview window, as you can see the masked area is completely different from that of the mask that is supposed to be on that frame. Ignore crappy lighting I turned it all the way up so I could see better masking a dark outline out of a dark background. The issue carries over into export and I cant find a way around it apart from just saying screw it vegas and doing it in an image editor instead. What this is actually showing is the mask outline from the previous frame.
The frame rate of the project and preview matches that of the clips and I have tried to delete the mask and start over but the second I click the frame with the mask tool the previous frames mask instantly appears on preview window (though not in pan/crop menu) I have tried also masking it out and saving the mask so I could just click on the frame and load the mask, again that did not work. Any tips would be greatly appreciated, hopefully it's me just being stupid.