Strange Misalignment

[Banshou]

How can I re-align this? I've been following doom builder 2 tutorials again after not mapping for many, many years, and i'm fairly certain I used a different editor back then.

[Jimmy]

Move the sector so the texture fits exactly in a 64x64 space on the grid. The squares are indicated with blue lines (by default) in 2D mode.

[Banshou]

Thank you.