In the existed world chunks of dirt appeared in the frozen ocean biomes

Since some update, many square chunks of dirt have appeared in my world in frozen ocean biomes. The same thing happens in frozen rivers. These squares of land were not in the world before. There is no water under them, just emptiness. It looks terrible. Also, on the old map you can see that there were no chunks of land here.
My children and I have been playing our world in the realm for over a year and a half now and the whole north in it looks spoiled (.
Screenshots examples
https://photos.app.goo.gl/eNwBbYWySkHpuLxE8