Roof section wall is rendered when Building:part=yes, wall=no

[Beakerboy]

I have a building where a piece does not have the wall on the roof; it is just a gabled roof. I have this tagged as
Building:part=yes
wall=no
building:min_level=1
roof:shape=gabled

despite this, the front and back “walls” are still rendered.
Do I need to add building=roof to the above? F4map seems to render this the way I was expecting.

[kekscom]

Give building:shape=none a try.

[Beakerboy]

That also does not work.