Thanks to lonefur for this one.
"We don't nerf premium tanks" - yea, right. Superpershing recieved a visually substantial nerf in frontal hull armor. See for yourself:
On the paper, the armor remains officially the same, but gamemodels3d show us that the frontal spaced armor got nerfed by cca 25mm - plus the armor angle is less steep, which means less bounces.