Transition between two rows on the home page

hi … can someone tell me how I can do the transition from line to line with the video with testimonials correctly or better.
Currently it looks as if the background image in the testimonials is too short. But it is not too small, it has 1920 x 1080.
The other transitions are all correct, but in this the dark background color is revealed when you scroll up. In the photo you can see it when you look closely.
What’s wrong in this transition? (my homepage:

Thanx for your help… :slight_smile:

Kind regards, Ina from Hamburg