It’s not the only bug that is introduced in this season for no reason.
Wall building is sometimes bugged in many ways:
-
build normally (as in season 7),
but end up broken:
-
quite often the edge of a mine cannot be walled. or told as wallable but at the end the wall left a hole or didn’t get built. The following wall was allowed at the first wall attempt, but end up a part of it didn’t get built.
this place can be walled only in this way