LegislationCode for worker phone doesn't import in HDL

Whilw using HCM Data loader sometimes the LegislationCode doesn't populate in the worker phone record.

I can't find the logic behind why somethimes it is popualting and sometimes it doesn't.

I don't get any errors during the load.

All the lines in the DAT file looks the same but for some workers (even in the same location) I can see the data in the worker communiction and for others not.