Hello @marks81797503,
Thanks for the question. This is a user to user forum, so I can't guarantee an answer here from the team but I will let them know about it. Other developers do enter into our forum from time to time, as well.
As I understand it, you cannot assume that the Render function will be called in sequential frame order. After Effects uses a multithreaded rendering engine, especially with Multi-Frame Rendering (MFR) enabled in After Effects 2022 and later. This means multiple frames may be rendered concurrently across different threads, and not necessarily in order.
Since I am not an engineer or a product team member, I will let others describe on what can be done to work around the issue. I hope the advice helps a bit.
Thanks, Kevin
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