The encounters for the Research Breakthrough reward has changed. From November 1, 2019 at 1:00 pm PDT until January 1, 2020 at 1:00 pm PST you may find one of the following Legendary Pokemon:
- Zapdos
- Articuno
- Moltres
- Kyogre
- Groudon
All of those Pokemon already have their shiny forms available, so you have another chance at capturing them!