Visible "Scratch" Line

Dear,

we have a creazy issue.
When have a couple of scene with some scroll that load the images from an excel file.
Everytime we enter in scene we see like a scretch that appear when we enter in scene just for a moment and then disappeard.
any idea

attached a short video and a picture to show you what i mean
Thanks

https://community.intuiface.com/uploads/db1757/original/2X/2/216b5b4e7ca5440dcb538a4b8824a882ad316128.mp4