Simple 3D transitions behave strangely
I have two simple clips and I have applied the simple Cube Spin transition but I am getting a very weird effect instead. It is difficult to explain so I made a short video so you can see what it going on:
I have tried with other simple transitions as well, like Flip Over with similar results. I am including a screenshot of the work screen in case it may help:

What could be wrong? I have tried looking in the forums but have not found the solution. Any help will be very much welcome.
