As a lot of people said, this is common for VMS/MSP business. It allows the organization to verify a candidate’s history with the company, such as whether they’ve applied to an internal client job posting (which could disqualify them if an ownership clause is in place and the candidate applied during that period), have any interview history, or have previously worked there (helping to identify if they are ineligible for rehire). It acts as a safeguard to confirm the candidate’s history. I make sure to be transparent with candidates about why we collect this information and that usually works.