New loading screen is not centered in windowed mode

Do you mean the new logo is not centered within the window, or the window itself is not centered on the screen? It seems to me that the logo is centered within the window, but the window itself might not be centered in the screen, though it's hard to tell for sure.

So if you press F11 to make it not a full screen the loading screen is not centered, so the loading screen is not centered on the screen.

It is indeed slightly off-centered: I counted 207 vs 211 pixels... This does seem rather petty though

It's very off-centered vertically.