Residency/Work waiver

My brother-in-law just arrived in the US with his green card in December.
His background is in IT, and applied for a position with a contract company that supports the Department of Veterans Affairs.
Everything looked good for him to receive a job offer, but they came back and told him he would not qualify for a Public Trust background check. They advised he needed to live in and work in the US for three years to receive a Public Trust approval.
I have not found this documented anywhere - wondering if it is accurate. And if it is, would a waiver be available for that requirement.
Thanks!

Permanent residents can be in a low or moderate risk public trust position, but not high risk unless there is an extraordinary need that cannot be filled by a U.S. citizen. The residency investigation requirement for a government credential is outlined in Appendix A of this document.

Thanks for the comment and link