[Kent Beeson] “So if when (next week) I make it 4 or 6 sec long and it works, what should I do since we need it about 2 sec?”
Video has limitations of what you can and can’t do, cleanly, with motion.
For instance, you must “roll” credits at only certain speeds so that the graphics’ motion doesn’t interfere with the trace of the scan-lines.
You might be seeing motion artifacts in your animation that are a result of the speed.
Can’t tell without further “tests”.