Bug that ruins buildings by removing stripes of blocks

We have encountered a bug on our Realm that keeps slicing away straight slices of blocks off our buildings, usually at the start of the building (see image), at the back of the building, or the sides, never in the middle.

It started happening 1 or 2 days after we bought and started our realm. We are never present to witness the bug in progress so we do not know when it usually happens. There are no other issues with the realm, it behaves correctly other than the block obliteration bug.