Found this on their Twitter. Same as the 800 they gave out previously for getting game of the year on App Store and google play store.
$18 of value for free. Enough for 5 wishes.
With your support, Genshin Impact was nominated for the "Best Mobile Game" and "Best Role Playing" categories at The Game Awards 2020.
We will be giving out 800 Primogems from December 12 to December 15. Thank you all for standing by us!