You mean the surface-slice intersection display in AFNI? This is done based on the coordinates of the surface and the coordinates encoded in the AFNI dataset header. So something must be different between the copies of the dataset (or surface) on the two systems. Now, SUMA sends the surface coords to AFNI (which doesn't directly read the surface files). You might check the output of 3dinfo on the 3D dataset, and see if the coordinate ranges displayed are the same on the 2 systems. The relevant lines look something like so:

Data Axes Orientation:
first (x) = Anterior-to-Posterior
second (y) = Superior-to-Inferior
third (z) = Left-to-Right [-orient ASL]
R-to-L extent: -79.950 [R] -to- 79.950 [L] -step- 1.300 mm [124 voxels]
A-to-P extent: -119.531 [A] -to- 119.531 [P] -step- 0.938 mm [256 voxels]
I-to-S extent: -119.531 -to- 119.531 [S] -step- 0.938 mm [256 voxels]

Or possibly the AFNIs or SUMAs on the 2 systems aren't uptodate.

bob cox