When the "ZUp" option was added to the fbx loader, it broke the previous behavior of converting to the OpenGL axis system. I'm referencing the following commit:
When the "ZUp" option was added to the fbx loader, it broke the previous behavior of converting to the OpenGL axis system. I'm referencing the following commit:

https://github.com/openscenegraph/OpenSceneGraph/commit/c168887e5e9da4e891904d11ccac8ddd60b0362d

This commit inverted the value of the "fSign" variable, but did not update the previous code that used the variable. I've attached the change that restores the original behavior when not using the "ZUp"

openscenegraph/osg,scrawl/osg,jtorresfabra/osg,openscenegraph/osg,jtorresfabra/osg,scrawl/osg,jtorresfabra/osg,jtorresfabra/osg,openscenegraph/osg,scrawl/osg,openscenegraph/osg,scrawl/osg