"Where will they watch a movie on Tuesday?"
Translation:Де вони будуть дивитися фільм у вівторок?
де вони дивитимуться фільм у вівторок? is correct answer, but not in duolingo
It might be "фільм" in accusative because it's a loan word, which sometimes follow their own patterns...
It's not true. Accusative of "фільм" is "фільм" not because it's a loanword (how about фільму and фільмом?..), but because it's inanimate and masculine.
Inanimate masculine and neutral nouns have Accusative = Nominative.
E.g. Я люблю торт (торт is inanimate, does not change form), Я люблю кота (cat is animate, has "-а" in Accusative)