Actually I just realized that i messed up with my schema, y was down before. So they just rotated the view 90°. Still, why X is down now? Should be up to match the 3d view?
I have news for you, the coords system was always inconsistent across viewports, ones claim forward is X and others Y, main, skeletal ones and static mesh ones
One is CAD-stylr (the new one, 5.6), one is for 3D modeling (5.5). As the real and virtual worlds are continuing to merge into one another, the CAD-style orientation is making kore and more sense.
Unreal just came a bit closer to reality.