That rotates the entire visual component, and not the map, which works rather poorly for any angle not at 90 degree exact offsets.
Knowing that it is not supported, is a help in itself. Now I don't have to look for it.
It would also likely be an issue with OSM, or similar, tiles with pre-rendered labels, which could end out being upside down.
Thanks for the great support, by the way. Not just answering but actually making a working sample to show your fix.