Title says it all. I don't know if this is WAI, but it makes these houses look kinda incomplete. Adding a top layer of lower oak slabs would bake them look much more beautiful.

The only exception is plains_cartographer_1.  The cause of this might be wrong setting of dimensions when these houses were created (Just like in MC-174071).

List of following houses also is unaffected, because they are even-number wide (double door) ands have stairs at the top.

1. plains_small_house_7
2. plains_butcher_shop_1
3. plains_fletcher_house_1  (note 1)
4. plains_library_2 (note 2)
5. plains_medium_house_1 (note 3)
6. plains_toolsmith_1
7. plains_weaponsmith_1

Notes:

1. Half of the roof is odd-number wide, and there are missing oak slabs
2. Has a roof that has an oak log at the top, so slabs would make it weird
3. Same as plains_fletcher_house_1.