I had a similar issue with my sequencer in UE5.1. For my case, the rendering was happening with the camera attached to a player start regardless of a camera in Movie Render Queue.
I am not sure if my experiences would help your case or not; however, I made three changes, and the rendering worked for me. Thanks to this community, I found a combination of workarounds that worked for me.
- Made Cine Camera Actor as spawnable (I think you already did this)
- Added “Create Level Sequence Player” for each sequencer to Level Blueprint (Movie Render queue in UE5.1 - Animated actor don't move when rendering - #2 by 7e9ej-8ek9)
- Updated Movie Render Queue configuration to use Game Overrides settings (Movie Render Queue Uses wrong camera when rendering - #13 by L.F.A)
I hope this helps your case as well.