Yeah, been there done that That’s definitely the pattern visually. But here’s the deal:

Rotate about X axis = rotate from Y axis to Z axis

Rotation about Y axis = rotate from Z axis to X axis

Rotation about Z axis = rotate from X axis to Y axis

Notice anything strange? Yeah, the positive rotation direction on the 2nd one (the one you’re asking about), goes backwards in the alphabet. Since X, Y, and Z are assigned columns 0, 1, and 2 and rows 0,1, and 2, this has the effect of making it look like the minus signs on the sin expressions are flopped.

What happened is that the starting point for our little 2x2 cos/-sin sin/cos matrix is cell 2,2 (Z,Z), and it wraps around the right and bottom edges of the upper-left 3x3, giving the appearance of flopping the signs on the sins.