Thank you for your patience while we addressed the issues with Team GO Rocket. We apologize for their extended absence, and we are letting you know that they are back.
To make up for the time Team GO Rocket was away, Shadow Zapdos will be returning as an encounter when you defeat Giovanni from Tuesday, June 1, 2021, at 12:00 a.m. until Thursday, June 17, 2021, at 12:00 a.m. local time.
Thank you again for your patience and understanding while we worked on this issue.
—The Pokémon GO team