Rendered rotoscope footage has glitch.

Hi, guys. Please help me out, I've been struggling with this glitch on my rendered footage.

It is a 1 second H.264 4K footage. I used Rotoscope 3.0. And I did rotoscope frame by frame and freeze it before the render. The frame rate is 59.94. I made sure the frame rate is matched with the original footage when I render. 

The render is fine when I use only roto brush, however, When I use the fine tuning edge brush on my footage, even though the preview in the composition looks fine, but after I render it, it appears to have glitches on some of the frames. I tried render as Tiff Sequence RGB+Alpha, Quick Time RGB+Alpha. It always gives me glitches.

Here is screen shot of the glitch I got: