From the looks of it, the problem was that Poiana Cofuri was covered by both the wood relation and the forest relation.

I converted Poiana Cofuri into a simple polygon and also converted the wood into a simple polygon in changeset/180030722.

Both the wood polygon and the Poiana Cofuri polygon are now inside way/85680320, so they should render correctly now.

I solved a similar problem in changeset/180030895. The grass area was also covered by the wood relation, so I split the wood relation into two parts so it doesn't overlap the grass area.