Drag problem ; component disappear while dragging

I made a drag animation from 3 frames to make a horizontal scrolling effect. All my animations are ok exept one (frame 2 to frame 1). Some components from frame 1 are fading out when I am dragging, but they show up when I release the drag. I can’t find the problem.. Here is a video to show it.

 https://vimeo.com/1131363351?fl=ip&fe=ec