But nevertheless it should display correct when i configure my window to any size.
Probably this works in any world but i havent tried yet. I uploaded the world with my kelp farm for you where the bug occurs. Just open the world, stay where you are and let the farm run for a few minutes. Then enter the water and search for kelps without a top block. Im not sure but it seems like they occure mostly on the other end of the farm far away, and are uncommon near the player. So make sure to wait at one end of the farm to maximize your chances. And remember not to save and reopen the world because it will get fixed.
Yes i have a backup and i uploaded it now. There is a upload size limit so i had to split the zip in 3 files.
Hmmm youre right. I tried recreating too and it was gone. I tried the new 1.14 stuff in this world and then flew thousands of blocks away in search for a bamboo jungle. The ony possible explanation could be that i flew in a circle somehow and found the bamboo that i planted before ...