This column appears to have once been part of a set of columns running north to south (another column (SU 6185) is visible in room G-11 in a nearly straight line from this column). At a later point, SU 6120 appears to have been incorporated into E-W wall 6089. Thus the column may be a remnant from an earlier open-air phase of the building that later became enclosed.
Walls of Rooms G-1, G-7, G-8, and G-12
Photo from south