Blocks disapearing.

I am sorry if there is a duplicate. I was swimming on creative peaceful, in a river surrounded by forest. I saw a giant empty gap, like when you temporarily see before it comes into view. I flew into it, and I started vibrating and I'd see the forest, then I wouldn't. It would not stop and I had to exit. I had seen it before and It was fine so It was a bug. Please help!

Steps to reproduce:
Go onto a Creative peaceful infinite world (Cheats on). Build a few things like a small parkour build and things like that. Put on the potions Leaping (8 min) and Swiftness (8 min) and swim In a river surrounded by a taiga forest. the seed was 56360848 if that helps.