I know it's the sprite aligner
Changes made in the sprite aligner aren't stored anywhere and will not persist through loading a game (including joining a server).
If the sprites look different on different PCs, either you've realigned the sprites on one of them this session, or they're running different versions of the GRF.
Double-checked with a new game on my desktop and a new game on my laptop. The alignment of the sprites for quicksilver is fine on my desktop but screwed up on my laptop.
I also tried replacing the file in the laptop itself. I am really confused.EDIT:
Problem fixed! Not sure why, but I had to remove a past version of the NewGRF from content_download folder.