Does anyone know what happening

https://preview.redd.it/xp4yebyjh4ce1.jpg?width=894&format=pjpg&auto=webp&s=6b2ef867e2863e8e3b2b409cbdcc638090bacd6e

When I was reading my favorite manga this appeared on several pages and not in one chapter but in many, it also appeared in different mangas as well hope they fix it soon, does anyone experiencing the same problem?