Repair Parts not being shown in PartWip table with SNStatus 'WIP'

After dispositioning an RMA to a job and assigning and matching Serial Numbers, when we try to do a Move Wip transaction on our repair parts as part of our repairs process, I’ve found that none of the parts get added to the PartWip table.

At what point do parts get added to this table? I can’t seem to find any information. Thanks.