Add a Pending Worker

Attempting to process a Add a Pending Worker (My Client Groups > Add a Pending Worker) for a rehire but I am getting this error message, "This person has an active assignment of the same type with the same legal employer Update their employment information to continue." It is occurring in Duplicate person check.

The person is terminating today; we need to rehire them tomorrow from Contingent to Employee.

This have been our working process until we switched to Redwood recently.

I understand with Redwood, there may be an ingest process that needs to run sometime but I don't know what could help resolve this.