Replaced Images not are shown

I do some ad videos for social media. The idea is to duplicate a szene and change the products and texts. When I replace an image, its simply not shown and not clickable. Just with the layers, I can access it again. 

In the preview in the left bar, the correct new image is shown. 

Here is the link: test-ad-video 

I tried to find a workaround like: 

• different file formats (png, jpgs, png in ai, psd)
• different browsers, cache clear, logout
• even in a rendered, downloaded mp4, the replaced pictures are not shown. 

I really have no idea anymore.