Rotoscoped clip blank in precomp and on export

I rotoscoped a clip and in the precomp and on export I get a blank black screen. 

it's a full hd 25 fps dynamic link video.

from the start I had an issue with rotoscoping, got the message that the comp didn't match the clip and I should make the comp 50 fps, eventhough clip and comp were both 25 fps. So I just set the comp to 50 fps to appease AE. Everything was fine the whole time, I exported multiple versions and it all worked, so I don't think that was the issue. Changing comp fps to 25 or 50 also doesn't fix the problem.

I kept working on it and now that I'm done, suddenly the pre-comp, the project panel miniature and on export the clip is just black. 

Everything looks fine inside the roto comp.

I have been having some memory issues, but now that I froze the roto, I don't. I've tried restarting ae and it doesn't help.