The following are possible causes of this issue.
We have confirmed that when users who have deposited Pokémon containing modified data directly into Pokémon HOME try to display that Pokémon on their screen or try to use GTS and Wonder Box, the screen got stuck and images are distorted.
Unfortunately, we regret to inform you that we do not provide any assistance regarding the issue caused by modified data.
We appreciate your understanding and cooperation regarding this issue.
In addition, please be aware that modified data Pokémon that caused the above issue cannot be received by any trade functions inside Pokémon HOME.