@verita84 It is how the Fediverse works, it is distributed and instances are independent from each other, means there is no central "hub" instance that distributes posts and their assigned hashtags which results in that instances have different posts and trending hashtags.

@verita84 By the way: The hashtag #Weihnachten is German for #Christmas . And most people here wish me "Frohes Fest", which is "Happy celebration". I then reply "Frohe Weihnachten" back.