I created the scenes with version 3.7.3.
Maybe these video examples with help explain my frustration.
I have two video clips:
1. a water splash into the sea
2. a sea floor animation.
With the default behavior (movie clips set to restart) the water splash scene plays from the beginning but as it fades into the next clip it suddenly jumps to the beginning.
When I uncheck the Restart behavior, the water splash scene fades out normally, but now it does not start from the beginning.
Maybe I am doing something wrong. If you'd like, I can send you the MadMapper projects I used for the above examples.