After spending hours rotobrushing, I finally got a mask that followed the outline of the subject, clicked the freeze button, ran a preview and saved it.
next day, I opened up the project with the latest save and found that the boundary line of the rotobrush was now way off. And this is before unfreezing it. Not just a little off - It has completely wrecked it.
Is a known issue or am I missing out some vital step to save the work I'd put in?