Hi SekeRob,
thank you for the tag about this issue. I've just finished this changeset: https://www.openstreetmap.org/changeset/152382021
You will see that I've deleted both turning limitations in Piazza Madonna della Cona: it's because, even if I think the grass area in the center works as a roundabout, there are no visible-from-satellite-imagery street signs marking it, so I preferred to delete for the moment, and maybe someone who knows better the zone will solve once and for all this doubt.