JOSM: "No style in multipolygon relation"

What does this error mean? I keep seeing those errors pop up when validating data for the French Cadastre building imports I’m working on.

I am also getting this error in JOSM version 3376.

The error seems to be originating from and I can find it in the source but I do not understand enough from “styles” to understand the cause.

Took some time but after reading better I think I understand the cause.

I did have a building with outer and inner members and had set in the outer “way” the tag “building=yes”, but this is not how it should be, the relation should have “building=yes” while both the inner and outer members should not have it probably.

This did solve the warnings I was seeing.