Chopped chunks, and Bedrock still appears in Deep dark caves

Hi, my name is Gabriel, I'm Brazilian, so I'm sorry for my English, I don't speak very well, I'm on version 21w08a of 1.17 caves & cliffs, and this bug happened that has a cut on my map, it doesn't seem to be a badly loaded chunk and in this other photo you can see that Bedrock is still showing up in the deep caves, I don’t know if this is on purpose, but if not, please fix it. I am loving this Update is the best update you will ever do, thanks and have a great day  I just found another new Bug, there are dark pieces scattered around the map