Cubase 11 artist video looping

When looping 2 bars of a video, the video will freeze until the second beat of the first bar each loop.
Project fps was set with the function “get framerate from video”.
Its a 25mb mp4 file, 30fps, H.264, 1080x1080 pixel.
Its not the first time, I had this problem also with a mpeg4 file.

Please help.