https://www.pcgamer.com/portal-2-co-writer-jay-pinkerton-seems-to-be-back-at-valve/

Portal 2 co-writer Jay Pinkerton appears to have returned to Valve, a year after he left the company.

2017 saw an exodus of Valve writers: Erik Wolpaw and Chet Faliszek, who wrote Portal 2 alongside Pinkerton, left in February and May respectively, and Pinkerton followed suit in June.