Masking messes up in after effects after rendering I've been masking all day today and everything has worked perfectly up until now. I did my usual mask and then rendered it but upon render everything screwed up. I have tried it multiple times and I've even gone as far as to re-import the clip and mask it all over again. The results were different but only in the pattern of the glitch. 

Im busy uploading the clips of the glitch right now so I'll just have to explain it for now. Basically everything looks perfectly fine in the ram preview window but when I render it, it separates the video around and the mask is completely messed up. Can someone please help me with this? It's incredibly frustrating when everything else today has gone smoothly. I'm using After Effects CC

Ram Preview Window: 



After Render:
Once the Rotobrush tool has been selected to use (assuming you used Rotobrush based on the pink outline) a small box in the bottom right of the comp will appear and should say "Freeze." Literally just press that and it'll freeze the mask... fixed my masking render glitch and I hope it does for you too! Best of luck, happy editing.