When adding scene strips to the sequencer, the wrong scenes were getting getting added if some were skipped. For example: Given 4 scenes (A, B, C, D) if you're trying to add the last 3 scenes (B, C, D) as strips to the first scene (A), it would ended up adding "A, B, C" instead of "B, C, D" as expected. Fix provided by Andrew (signal9).