Bret

I think this may be occurring due to a misbehaving cat. Seriously! Let me explain:

In the structure file that defines the savanna cartographer house (savanna_cartographer_1.nbt), item 138 in the blocks list is an upward-facing jigsaw block with *target_pool*: minecraft:village/common/cats among its nbt data. It's positioned at (4, 0, 4), which is two blocks directly beneath the missing floor plank.

So this jigsaw piece allows a cat to potentially spawn beneath the stilted building, which is admittedly a cute spot for a cat to cozy up. And two blocks of vertical space seems like more than enough room for a cat. However... assuming the jigsaw piece connects to the cat "structure" that's defined in structures/village/common/animals/cat.nbt, it's not. The cat "structure" is 3 blocks tall and consists of a jigsaw block, a DATA-mode structure block, and an air block at the top. Thus, when a cat is given a spawn point under the cartographer house, it inadvertently replaces the middle floor plank with an air block.

This theory also explains why the issue doesn't happen all the time—since jigsaw blocks don't always connect everywhere they're able to, the cartographer house keeps its full floor when the jigsaw block stays unconnected.

The problem of "No mason houses in Savanna Village" seems to be caused by an issue with how the structure itself is defined.

Digging into the relevant NBT file (assets/structures/village/savanna/houses/savanna_mason_1.nbt in the Android .apk), the palette entries don't include any jigsaw blocks, hence no jigsaws in the blocks entries. This stands in contrast to every other building in every biome (I checked!)—all of them, with the sole exception of savanna_mason_1.nbt, contain a jigsaw block with *attachement_type*: minecraft:building_entrance. (For what it's worth, the savanna_mason_1.nbt file in the Java edition file does include this essential jigsaw block.)

In other words, the savanna mason house technically exists in the game. But because it doesn't contain a jigsaw block to connect to village streets, it's unable to actually generate within savanna villages.