Persistent Disappearing of Layer for One Frame Only

I'm rendering a screen inside a phone. A pretty common thing. I'm using a screen recording from an iphone to place in the phone model in AE (using Element 3D).  None of this is weird, everything is working fine – except for this one comp. There is one frame where the screen recording disappears from the phone. There is media there. I've tried using different frames, moving things around, but for whatever reason at this one moment in my timeline, it thinks the media has disappeared. 

I know this isn't explained well, so I provided a video. I cannot find a logical reason for this. I thought maybe it was because frame rates on iphone videos are not constant (and maybe this extends to screen recordings), so I kept selecting different frame, but to no avail. 

I'm on macOS 12.6.3, AE v23.2.1 (the latest, as of this post).