Hi, the changes I made are in the eastern part of the forest (which renders correctly, at least for me) and are OK according to JOSM internal validator

I tried marking two tiles in the forest dirty to force rerender, they look correctly now.

In this changeset you replaced the Austrian-German bi-national quadripoint near Jungholz by two nodes, only to eliminate the touching point in the OSM inspector. In reality, the boundary of Austria has the touching point, see e.g. http://jungholz.enclaves.org/
Is there a good reason to make this chage?
If not, can you please revert it?

Sorry, but the multipolygon is incorrect.
The problem are the three parts of the forest that are completely surrounded by the inner paths.
See eg the way/448462938 which should be both inner and outer (depending which part of it one takes) for the multipolygon.
See
http://tools.geofabrik.de/osmi/?view=areas&lon=15.77242&lat=47.73476&zoom=16

See also osm.wiki/OSM_Inspector/Views/Areas#Way_in_.3E1_rings

Can you please correct it yourself?