From what I understand, this ‘burrowing’ is allowed by law. Clinton did it in a massive way as he left office. The reason for doing it is because these people are almost impossible to fire by the next administration(s).
Since their jobs are protected by law, one of DJT’s first acts as President in January 2025 should be to transfer any and all employees burrowed by either Obama or Biden to offices in Fairbanks, Alaska, International Falls, Minnesota, or any other location with harsh weather.