I was checking Random Minecraft seeds and I found this Giant box in One.
MC-131150
Giant Box Generated In My Minecraft World I just made.
Resolved
Duplicate
0
This type of glitch is known as a chunk glitch. usually caused by closing the game before it can save properly which corrupts the file you can search for more information about it here.
-> https://bugs.mojang.com/browse/MC-89269?jql=text%20~%20%22chunk%20glitch%22
As a temporary fix for this world, you can use the fill command to replace the block with air. a tutorial for that is here
-> https://www.youtube.com/watch?v=r0rVf-VBxM8