Chapter points
A chapter marker cannot be within 2 seconds of another chapter marker, or the end of the video in Express Burn.
Technical note
Chapters are commonly used in DVD or Blu-ray for easy navigation. Each chapter has a time, which is on MPEG I-frame markers rather than time-based, it may happen that a chapter starts a bit too early when played.
If two chapters are too close, they may be moved to the same time point.