I'm glad you were able to figure it out for yourself.
I'm copying below what my colleague sent me; he's done chapter breaks for many distributors as well as for FilmHub. This might be useful for someone else.
1. Feature films or concert films must have chapters. Short form, non‐episodic video do not require chaptering.
2. Chapter titles must match the chapter titles used in the physical release (DVD or Blu-Ray), if available.
3. Chapter titles must not include special characters, such as or . Exceptions are made when these characters are part of the official film title (for example, Wall•E).
4. If no chapter titles exist, use generic alpha-numerics to indicate chapters, such as "Chapter 1, Chapter 2, Chapter 3," et cetera.
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