Let me clarify, a SINGLE frame disappears at the 4:00f mark, where the two precomps meet. When I drag the second precomp 2 frames to the left and connect the first one, it temporarily solves the issue - all frames appear like normal.
Without seeing the structure of the project, it's hard to say. Those lines likely indicate that the precomp is playing backwards instead of forwards.
Okay if that's all those lines mean, then that makes since. It's a lower-thirds animation that plays forwards to introduce text and then I guess plays again backwards to retract the text. Here are more images to give you an idea:
Below is the whole project. I'm using Typography 01 and Render under the Banner folder.
Below is the Render composition. I guess the person that created the project just used the Typography 01 composition forwards and duplicated it backwards at a higher speed.
Below is the Typography 01 composition. This is used in the Render Composition above, maybe there's an issue an here that will resolve everything?