Closed apps shadow in the screen background
I bought a Brand New MacBook Air M1 25/01/2020. while I was using the laptop I saw a closed program shadow in my login screen. This problem is not always .... I have been using the computer since today morning but there was no problem ... I saw the problem when I changed the desktop background picture. I tried some black pictures and then I noted this issue. there was no issue when I shutdown the laptop for a while and start it . but after using it for a while, I saw this problem again. What can I do for this? Can I replace a laptop ?(I have a Warranty). Is this a software issue or display issue?
MacBook Air 13″, macOS 11.0