Why it happens
- Picture was cut first and sound added at the end, without aligning to event points.
- Clips have mismatched frame rates and get stretched or drop frames on import.
- A shot was speed-changed or trimmed without moving its audio with it.
How to fix it
Align dialogue, lip sync and key sound effects first, then fine-tune the picture cuts.
Log the start and end time of each action sound and place it on the exact frame of the event.
Set the project frame rate to match the source footage and confirm all clips match before importing.
Group picture and audio before speed changes or trims, then recheck frame by frame.
Prevent it next time：Cut to sound first and picture second, and fix the project frame rate from the start.