Tina Goldstein is a popular character in the Fantastic Beasts franchise, portrayed by actress Katherine Waterston. She appeared in the first two Fantastic Beasts films as an Auror for the Magical Congress of the United States of America (MACUSA) and was also a love interest for the protagonist, Newt Scamander.

Fans were disappointed to learn that Tina would not be returning for the third installment, The Secrets of Dumbledore. The production team has not released any official statement regarding why they excluded her from the story. However, there are a few possible explanations.
Firstly, it could be a creative decision. J.K. Rowling, the writer, and David Yates, the director, may have decided that the plot did not require her presence, or that her character had already been developed enough in the first two movies.
Another possibility is scheduling conflicts. Katherine Waterston has worked on several other projects since the last Fantastic Beasts film, including Raised by Wolves and White Noise. If she was unavailable to film The Secrets of Dumbledore, the team may have decided to write Tina out of the story rather than recasting the role.
Thirdly, the story may simply not require her character. The Secrets of Dumbledore is said to focus on the character of Albus Dumbledore, with Jude Law reprising his role. The plot will explore Dumbledore’s relationship with the dark wizard Gellert Grindelwald, played by Mads Mikkelsen. It’s possible that Tina’s character simply does not fit into this particular story, which is more focused on the Dumbledore-Grindelwald relationship and the larger wizarding world.
Lastly, pandemic-related changes may have contributed to her exclusion. The COVID-19 pandemic has caused many changes in the film industry, including delays in production schedules and changes to filming locations. It’s possible that Tina was originally intended to be a part of The Secrets of Dumbledore, but changes to the production schedule and other pandemic-related factors led to her character being written out of the story.
In conclusion, the reason for Tina’s absence from The Secrets of Dumbledore remains unclear. Fans of the Fantastic Beasts franchise will have to wait until the movie’s release to see how the story unfolds and whether Tina’s absence is explained or addressed in any way. Regardless of the reason for her exclusion, many fans are disappointed that Tina will not be returning for the third film and hope to see her in future installments of the franchise.