This issue is originated by the fact that the servo galvo and the DGS are following two different convention for the WFS segment order:

The galvo servo from initial TAMA is following the convention in pic 1 (take from this document), while the DGS is following the convention on pic 2 (KAGRA convention).

The cables from the WFS DC segments have been connected into the galvo servo followig the convention from KAGRA/DGS and this resulted in a swap between X and Y error and correction signals.

We decided to keep the current configuration to be coherent with the DGS beam position monitor. Note that for WFS1 the cable for the correction signal for X and Y were originally inverted by mistake.