Symbol not exporting in huge file
I have created a huge file for a multi screen display - 7860x1080 px.
In the past i have created them with a simple static background with some animated text over the top, including 3D tweens.
In the most recent version, I created an animated background by importing an image sequence at 25fps from a video. As a result the filesize is huge, but I figure this shouldn't be an issue because once its all exported the file size is easily manageable.
However in the version with the animated background, my 3D tweened object don't appear in the .mov export.
I can copy the 3D tween to a new file, and it appears fine when exported, but once the background is added, the symbol stops being exported.
I'm aware this is probably something that should be being done in AE, which I'm currently looking into, but any help in the meantime would be much appreciated.
Has anyone come across this issue before?