chunk errors random crashes and other

when I go into certain worlds they crash and leave chunk errors on my map my latest bug was a 16 by 14 by 256 block delete and I cant place or walk on the error this has happened several times but I thought it had to do with the snapshot but I tried it without the snapshot with the old launcher and it crashed twice then I tried a third time and then I still saw the chunk error.
I am using the new snapshot and I have been using them up to date on my maps.