Hi!
I am not sure if this is a solution, but once I changed the background images from your assets folder to my own images I noticed the bug was gone. (Bug: the background changes for a few miliseconds to some other one once the loop is back on start).
I noticed the only change I made was that all my image assets are PNGs. With JPGs I always have this bug, not with PNGs.
I hope this helps :)
Thanks for the great tutorial 🥇